OT2 Proposals

Having retained and preserved pristine material from the Solar Nebula at the moment of their accretion, comets contain unique clues to the history and evolution of the Solar System. Important diagnostics of how and where cometary materials formed are contained in isotopic ratios, since isotopic fractionation is very sensitive to chemical and physical conditions. Following the discovery of an Ocean-like D/H ratio in the water of the Jupiter-family comet 103P/Hartley 2 using HIFI (Hartogh et al. 2011, Nature, in press), we propose to obtain a high-accuracy D/H measurement in a long-period comet from the Oort cloud. Since measurements in Jupiter-family comets have only been acquired with Herschel, it is important to get a set of measurements for Oort cloud comets with the same instrumentation. Confirming the observed dichotomy in D/H ratio for long-period versus Jupiter-family comet would be the first clear compositional difference between these two dynamical classes of comets. The values and statistics of distribution of the D/H ratio in the two classes will improve our understanding of their origin in the Solar System, with implications for the dynamical evolution of the early Solar System and for the delivery of water and other volatiles to the Earth.

This is a follow-up proposal to our ongoing OT1 proposal "Detecting the Largest Rings in the Solar System--Dust Rings from the Irregular Satellites" (OT1_ddan01_1). We seek to re-image each field visited by our OT1 observations once the planet and its rings have moved out of the scan. This will allow us to accurately subtract the galactic background that currently obscures our data. The cirrus emission represents the last barrier to accurate photometry at uninvestigated wavelengths of the newly discovered Phoebe ring at Saturn(Verbiscer et al. 2009), as well as the possible discovery of analogous rings around Uranus and Neptune. The total time required (including overheads) is 11.8 hours as estimated by HSpot.

In 2015, Pluto and its system of satellites will be explored by the New Horizons space mission. Pluto is the most prominent representative of large Kuiper-belt objects with volatile ices (N2, CH4, CO) on their surfaces. Due to its elliptic orbit and strong polar inclination, the large seasonal and spatial variability of the insolation is expected to drive global scale transport of the volatile ices, whose thermal balance determines the atmospheric state. Recent observations of Pluto of various kinds have revealed that it is undergoing seasonal evolution, with changes in its atmosphere, surface spectrum, and thermal emission. In particular, Spitzer observations over 2004-2007 indicated a surprising dimming of the dwarf planet at thermal wavelengths, most probably associated with extension of the coldest, N2-ice dominated, regions. We propose to measure the thermal lightcurve of the Pluto/Charon system (i.e. the rotational variation of its thermal emission) with PACS and SPIRE in order to (i) assess the changes in the ice distribution (ii) determine the emissivities (spectral and bolometric) of Pluto's different terrains (iii) determine their thermal inertia on seasonal timescales. These parameters are needed to constrain volatile transport and general circulation models, and to put the upcoming New Horizons measurements in a broader, time-evolving, perspective.

Observations of Saturn with HIFI, performed in 2009 and 2010 have revealed absorptions in the core of several emission lines of water from Saturn's atmosphere. They are due to absorption from water in the “Enceladus water torus”, a cloud of material originating from Enceladus' active plumes and spreading around Saturn to form a broad toroidal structure centered at Enceladus' orbit. These data permit to determine water column densities in the torus equatorial plane and allow a first estimate of the torus vertical extent and dynamical structure. Comparison with physical models indicates an Enceladus source rate of ~10^28 water molecules s^-1, and suggests that Enceladus' activity is the ultimate source of water in Saturn's atmosphere (Hartogh et al. 2011). These H2O observations thus provide an entirely new method to probe physical conditions (density, structure, kinematics) in the Enceladus torus and to monitor Enceladus’ venting activity. As such, they are highly complementary to the Cassini measurements, which characterize the source region but cannot sample water away from Enceladus and have led to contradictory results as to the stability/variability of plume activity. Additional observations of these H2O lines have been acquired in December 2010 and July 2011. We propose to (i) continue to monitor the variation of these absorptions with viewing geometry and time, taking advantage of the change of aspect in the Saturn system over the upcoming years (ii) search for H2O emission directly originating from the torus (iii) monitor the water emission from Saturn, which from the July 2011 observations was shown to be enhanced in relation by to the current major storm developing in Saturn's Northern hemisphere. The ensemble of data, along with torus models developed by our team, will provide us with an improved understanding of the torus three-dimensional structure, the excitation conditions for water in the torus, and the variation timescales of Enceladus’ cryo-volcanic activity.

Our primary goal is to increase our knowledge about the outburst and split comets using the both the Herschel Space Observatory and ground-based telescopes in order to combine the thermal infrared and visible domain data. Our comet targets are selected from different orbit classes as like Ecliptic Comets (ECs), Nearly-isotropic Comets (NICs), and Main Belt Comets (MBCs). These are 17/PHolmes (EC), the most puzzling comet underwent already two superoutbursts, 133P/Elst-Pizarro (MBC) which shows recurrent cometary activity, 213P/Van Ness (EC) is a split comet with two components, and C/2010 X1 (Elenin) is a split and outburst comet. Comparison of the thermal infrared and visible range observations allows to investigate the shape and possible surface inhomogenities using infrared flux curves and light curves in the visible. We will use the unique capability of the PACS instrument of the Herschel Space Observatory. The measurements for all targets are performed in scan map mode, observations are done priimarilz in the PACS blue (70 micron) band. By means of this observational technique we will reach 1/1.5 mJz in the 70 micron band. The proposal will cover total observing time schedule of 13.9 h.

The detection of water ice on Asteroids (24) Themis and (65) Cybele and comet-like activity on some asteroids (so-called main belt comets) have recently provided evidence for water ice in the outer asteroid belt. This supports the suggestion that water in the Earths oceans may have been delivered from the outer asteroid belt.

In 2010, for both (24) Themis and (65) Cybele, results were published from rotationally resolved near-IR spectra that indicated the presence of widespread ice on their surfaces, a detection which served to imply a wider prevalence of water among minor Solar System bodies. However, this detection has since been challenged in 2011 with an alternative interpretation of the absorption at 3.1 microns being suggested.

This proposal requests 2 hours of the Herschel Space Observatory’s HIFI instrument scheduling time, 1 hour observation per asteroid, to provide conclusive evidence of the presence of water ice on these asteroids through the detection of outgassing via sublimation of this water; a result which has profound implications on the understanding of the origin of water on our planet.

Titan's atmosphere has one of the most complex photochemical cycles in the solar system and results in a vast array of organic compounds containing H, C, N, and O. Understanding Titan's atmosphere has been a major scientific goal since the Voyager era and was one of the main drivers for the Cassini mission. When Cassini first flew through Titan's upper-most atmosphere its mass spectrometer discovered unprecedented levels of ammonia (NH3), which were orders of magnitude greater than those predicted by the most up-to-date photochemical models. This discovery suggests serious deficiencies in our present understanding Titan's photochemical cycle.

Based on the Cassini upper atmosphere measurements, it is now suspected that NH3 is present throughout Titan's bulk atmosphere in much greater quantities than previously expected. This has recently lead to an additional NH3 production pathway being hypothesised - which we aim to test in this proposal. By observing NH3 spectral emission lines around 1764 GHz with Herschel's HIFI instrument it will be possible to determine the bulk atmosphere NH3 abundance for the first time. This will allow us to probe missing links in Titan's ammonia and nitrogen cycles and dramatically increase our understanding of Titan's atmosphere and photochemical processes in general.

One of the Infrared Space Observatory's most important results is the detection of H2O and CO2 in the giant planet stratospheres. The presence of a condensible species (H2O) above the tropospheric cold trap implies an external origin of H2O. This oxygen supply, which manifests itself also through the presence of CO2 and CO in these atmospheres, may have several sources: a permanent flux from interplanetary dust particles, local sources (rings, satellites), or large comet impacts. However, observing CO in the stratospheres of the giant planets does not automatically imply only an external origin of this species because there is no condensation sink at the tropopause for CO. Thus, it can be transported from the deep hot interior of the planet to the stratosphere. CO can have either an internal origin, an external origin or a combination of both. Spectrally-resolved, high signal-to-noise ratio and spatially-resolved (when possible) observations are needed to disentangle the various sources. While Jupiter, Saturn and Neptune have all an external source of CO, probably of cometary origin, and an internal source (not yet demonstrated but likely in Saturn), the situation remains unclear at Uranus despite the detection of CO from its 5 micron fluorescence. So far, we have not detected CO from the ground in the (sub)millimeter range but we obtained a tentative detection of the CO(8-7) line with HIFI in July 2011 in the framework of the HssO Key Programme. Because external sources of CO seem to be active for all the other giant planets, we propose to observe Uranus at the frequency of the CO(8-7) line with HIFI in order to confirm our tentative detection in the submillimeter range. We will obtain a spectrally-resolved and high signal-to-noise ratio observation of the lineshape that will enable us to retrieve information on its vertical distribution. Thus, we will be able to discuss the origin of CO in Uranus from this observation.

Saturn's usually slowly evolutive seasonal cycle has been disrupted in December 2010 between 20°N and 50°N by the outbreak of an unexpected huge storm system. First Cassini/CIRS and ground-based observations have shown that temperatures, winds and chemistry have been rapidly affected by the storm in the stratosphere. For instance, a temperature increase of 50K over 60° in longitude has been measured by Cassini/CIRS in May 2011. We propose to take advantage of this rare opportunity to use Herschel’s mapping capability with HIFI and PACS to probe the vertical structure of this unique storm and derive constraints on its formation processes. We will map the emission of H2O at 66 and 67 microns and CH4 at 120 microns and 1882 GHz to measure the temperature between 0.1 and 100 mbar in the stratosphere and to check for any disturbance in the H2O vertical profile. Such disturbance would be due to the injection of massive amounts of tropospheric H2O into the stratosphere by the storm. Because this storm seem to undergo a slow evolution, we propose to monitor its temporal evolution by observing the proposed set of maps once in each of the three remaining observability windows of Saturn.

Massive star formation remains a poorly understood phenomenon, largely due to the difficulty of identifying and studying massive young stellar objects (MYSOs) in the crucial early active accretion and outflow phase. Large-scale Spitzer surveys of the Galactic Plane have yielded a promising new sample of young MYSOs with outflows, which are likely actively accreting: based on their extended 4.5 um emission in Spitzer images, these sources are known as "Extended Green Objects (EGOs)" from the common coding of three-color IRAC images. Extensive ground-based follow up observations revealed that the EGOs are indeed related to massive outflows from young systems with very high accretion rates (10^-3 Msun/year). They also revealed a wide variety of properties: some MYSOs appear in clusters, others are isolated, some are molecular line rich, others not. To test the hypothesis that these differences reflect evolutionary effects, we propose SPIRE/FTS and HIFI observations of 4 EGOs. SPIRE/FTS spectra of the 12CO and 13CO rotational ladders and HIFI spectra of selected CO line profiles would yield shock-excited gas temperatures and masses, constraining the current outflow (and thus accretion) activity in a more direct way than is possible in low excitation tracers with ground-based telescopes. HIFI observations of H2O and NH3 line profiles and abundances would provide independent present day outflow activity indicators and records of the shock history, as these species are formed above temperatures of 230 and 4000 K, respectively, and preserved in the post-shock gas. This unique Herschel data set would also address outstanding questions about the disputed origin of the Spitzer "green" emission, interstellar H2O/NH3 abundance ratios, and the role of outflow feedback in models of cluster formation.

The Galactic high velocity clouds are typically 10 kpc from the Sun, with many moving at high speeds through the hot (million Kelvin) gaseous halo. In addition to photoelectric heating, ram pressure can thus also heat the clouds. These heat sources are balanced by the infrared forbidden line emission of C II and O I, providing a direct window to the relevant heating processes. One particular anti-center HVC is a likely CII 158 um source, based on our study of the COBE FIRAS 158 um map and all-sky HI data. Unfortunately, the FIRAS resolution (7 degrees) is too poor to determine the location relative to the cloud and contains no useful velocity information. With the proposed Herschel PACS spectral study, we will determine whether the CII enhancement occurs at the leading side of the cloud as it falls onto the Galaxy, and the degree of ram pressure heating compared to photon heating; the C II velocities also provide crucial information. In addition, we will determine the temperature and abundance of carbon and oxygen, which will indicate if the HVC is Galactic (solar metallicity) or low-metallicity accreting material.

The process by which planets accrete and grow are not fully understood. A unique insight could be provided by measuring the size distribution of the collision products in young systems, as it would constrain their dynamical state and the composition of their planetesimal bodies. We propose to observe twelve systems with SPIRE, determining the particle size distribution slope from their long wavelength photometry, breaking the size distribution/distance degeneracy in their SED models by combining our new data with existing Spitzer and IRAS photometry and determining the geometry of the systems.

The thermal signature of planetary debris disks typically originates from particles up to a thousand microns in size and it typically takes on the order of twenty to thirty million years for particles of that size to reach collisional equilibrium in warm disks and 100 to 200 Myr in cold disks. The distribution of dust in the earliest stages of evolution should be more reflective of the collisional fragmentation function and the effects of aggregation between the smallest particles than the collisional cascade equilibrium distribution function, which is reached at a later stage. The slope of the SED in the Rayleigh-Jean regime is in direct relation to the slope of the particle size distribution. While the particle size distribution in older disks can be approximated via models, it is completely unknown for young systems. With SPIRE we will be able to directly observe the particle size distribution in the earliest stages of debris disk formation, which will then shed light on the nature of planetesimal bodies and their formation!

Massive outflows are known to drive a special chemical complexity due to the strong shocks they produce in the surrounding molecular material. Hydrides are key ingredients of interstellar chemistry since they are the initial products of chemical networks that lead to the formation of more complex molecules. Given their small reduced masses, their rotational lines lie at short sub-mm wavelengths, which are almost unobservable from the ground. With the HIFI instrument on board of the Herschel satellite it is now possible to observe the strongest transitions of light hydrides, in particular H2O but also the reactive ions OH+ and H2O+, which are thought to play a crucial role in the formation of OH and H2O. HIFI early results revealed that indeed water and its cation H2O+ are abundant components of the interstellar medium. The additional HIFI detection of OH+ is an important confirmation of the gas-phase route of water. Although key programs have targeted few massive sources to map the water distribution, a comprehensive study including other important hydrides such as OH+ and H2O+, and covering sources in different evolutionary phases, has not been provided yet. This project proposes a dedicated study of water and related hydrides (H2O+ and OH+) in massive protostellar outflows in order to: a) trace the water distribution throughout the different evolutionary phases of massive star formation, b) determine the contribution of water emission in the energy lost by shocks, and c) unveil the role of ions such as OH+ and H2O+ in the production of water.

The formation mechanism of high-mass stars and the different evolutionary phases involved in the process, still remain unclear. We recently performed single-dish HCO+ and SiO observations at millimetre wavelengths of a sample of high-mass star forming regions in search of molecular outflows. Our results indicate a decrease in the jet/outflow activity with the luminosity to mass ratio, L/M, a distance-independent parameter considered to be an estimate of time or evolutionary state. These findings are analogous to what is found in the low-mass case, which suggests that high-mass stars may form in a similar way to low-mass stars. However, uncertainties such as the unknown inclination of the outflow axes and the poor knowledge of HCO+ and SiO abundances call for more precise measurements of the outflow mass loss rates to assess the variation of this quantity with time and also associate them with the accretion rate, a crucial parameter to understand high-mass star formation.

We therefore propose to image a suitably selected sub-sample of the regions with outflows with PACS in the OI 63 micron line. According to theory, this line can be related to the outflow mass loss rate, which can thus be easily obtained. Combined with our single-dish outflow maps, and with data from the Hi-GAL survey for a better estimate of the luminosities and masses, we will calculate all the relevant parameters to assess the dependence of outflow rate on time for high-mass stars. We will also observe the OI 145 micron line to check for possible opacity effects, the CII 157 micron line to verify the presence of photo-dissociation regions which could affect the OI emission, and a number of CO transitions with both PACS and SPIRE to analyse the excitation conditions of the outflows.

Cosmic rays (CR) are ubiquitous in the Galaxy and have the important role of ionizing the dens gas of the ISM. New Herschel observations have shown the huge diagnostic power of the OH+ fundamental transition to measure the CR ionization rate in diffuse clouds. Based on previous "serendipity" observations toward OMC2-FIR4 within the KP CHESS, we discovered a tenuous foreground cloud absorbing the fundamental OH+ line. Similarly, Gupta et al. (2010) found an OH+ absorption component at a similar velocity towards Orion KL and estimated a large CR ionization rate more than 10 times larger than the average value observed in diffuse clouds . We propose here to roughly map the CR ionization rate in the direction of the OMC2 and OMC3 complex to understand its extent, nature, and, finally, the source of ionization.

Many young main-sequence stars are surrounded by dusty debris disks, but only very few of them have a detectable gas component. In our APEX survey we discovered two new debris disks containing a substantial amount of molecular CO gas. One of them, the 30 million-year-old HD 21997, is the oldest known gaseous debris disk, making it the best candidate for containing CO gas of secondary origin, produced by sublimation of planetesimals, photodesorption from dust grains, or vaporization of colliding dust particles. We suggest that our discoveries together with the already known objects beta Pic and 49 Ceti form a distinguished group of debris systems that may represent the first stage of gas evolution after the primordial phase. Here we propose new Herschel observations to deduce the physical properties and the origin of gas in our targets, and study the possible physical processes of gas production in the secondary origin scenario. Our immediate objectives are the following: 1) Detection of [O I] 63um and [C II] 158um lines in our targets; 2) physical characterization of the gas/dust disk components; 3) establish the origin of gas and 4) comparison with beta Pic and 49 Ceti, and studying evolutionary aspects. The observation of atomic emission lines in such disks will provide a valuable information on the composition of the released gas and thus on similarity of the volatile composition of Solar System comets to exosolar planetesimals, potentially playing key role in the delivery of volatiles to exoplanets. The study request 9.2h observing time.

Nearly all young stars harbour circumstellar disks, that serve as the reservoir for mass accretion onto the star, and later become the birthplace of planetary systems. After the disappearance of the gas component from the disk a dusty debris disk is formed that is believed to mark the location of the planetesimal belt as well. For outlining the evolution of such debris disks traditionally open clusters and field stars were studied, however we argue that the recently discovered young moving groups are more suitable objects for such analyses, due to their proximity and good coverage of the first 50 Myr period of the planetary system evolution. In this proposal we request 70/160 um Herschel/PACS photometric observations for so-far unobserved moving group members. These observations will provide a complete coverage of all known members within 80 pc of five nearby young moving groups (beta Pic Moving Group, Tucana-Horologium, Carina, Columba, and Argus), in the A to K spectral range. Based on the new observations we will identify new debris disks, characterize the disk population within individual moving groups, and study disk evolution by comparing the groups of different ages. The results will be used to verify predictions of the self-stirring model of the evolution of planetesimal disks. We will also compare the properties of debris disks in groups of the same age, looking for additional 'environmental' parameters that affect disk structure over a whole moving group. Our study will be a significant contribution to the census of debris disks in young moving groups, increasing the number of observed sources by a factor of 1.5. Since Spitzer could perform only a limited census and the so-far approved Herschel programs added very few additional moving group obervations, our programme is expected to have a high legacy value.

Bowshocks around runaway OB stars are some of the most spectacular objects in the mid/far infrared, covering in some cases as much as half a degree across the sky. The bowshocks are essentially enormous gas shells contained by ram pressure where the dust trapped in their interiors reprocesses the UV flux from the parent OB stars and re-radiates it in the infrared. The pressure balance between the stellar wind and the ISM, also implies a tight relationship between their physical properties, and therefore, bowshocks from runaway stars provide a powerful tool to probe the interstellar medium and/or the properties of the OB stellar wind. The formation of these shells requires very efficient cooling that is expected to take place through the emission of a wealth of atomic fine structure lines, like [OI] 63.2 or [NII] 205.2 micron. Because the diffuse nature of these shells it has been very difficult to confirm this expectation using spectroscopic observations. In this project we propose to use the PACS spectrometer to observe the zeta Oph bowshock in order to better understand and constrain the physical conditions of its gas shell, its dust properties, its turbulence, and in such a way that will allow to use zeta Oph as a template to make sense of the physical properties of the many more runaway bowshocks are continuously being discovered.

Disks of gas and dust around young stars evolve from massive, gas-rich protoplanetary disks to tenuous disks mainly of dust. These dusty disks, now called debris disks, are produced by colliding and evaporating planetesimals, young analogs of Solar System asteroids and comets. They are intermediate between dense protoplanetary disks and mature extrasolar planetary systems.

Herschel disk surveys have found a number of systems with exceptionally cold debris dust, which is likely a sign of planetesimal belts at surprisingly large distances from the central stars (> 50 AU for a solar-type star) and/or peculiar dust properties. These systems will provide key tests of theories for debris disk evolution and planet formation. However, observations at longer wavelengths are urgently needed to 1) truly measure the dust abundances and temperatures, 2) find any dust components at even colder temperatures, and 3) permit accurate modeling of the dust properties and spatial distributions.

Therefore, we propose confusion-limited SPIRE photometry at 250, 350, and 500 microns for 24 debris disks in nearby young associations, to populate an important region of their spectral energy distributions. The targets are located in the TW Hydra Association, the Upper Scorpius Association, the Beta Pictoris Moving Group, and the Tucana-Horologium Association, spanning a crucial age range for debris disk evolution (10 to 30 Myr). The proposed observations, which are uniquely sensitive to ultra-cold dust, require a total of 3.2 hours. Our targets have all been observed with PACS but not with SPIRE. This proposal is independent (stand-alone) in its goals and execution: in short, we are looking for ultra-cold dust in a sample of young debris disks. However, the final dataset will also increase the legacy value of several other Key Programme datasets.

M dwarfs are the most populous stars in our local universe, and yet we know little about how they form and how often they form planetary systems. Due to smaller stellar radii, larger gravitational reflex motions, and closer habitable zones, M dwarfs are ideal targets for detecting the first terrestrial mass planets in the habitable zone and will be high priority targets for years to come. Therefore, studying the population and physical characteristics of circumstellar disks around M dwarfs will provide insights into this unique environment in which we hope to find habitable planets. Here, we propose to use the Herschel telescope to collect far-infrared (100 & 160 micron) photometry of a sample of 32 M dwarfs. Our sample represents the best candidates to contain detectable debris disks based on youth and proximity to Earth. Our science goals will be to characterize the physical properties of these disks such as temperature, extent and composition thereby gaining a deeper understanding of the formation and evolution of the planetary systems around low-mass stars. This will also identify the best targets for terrestrial planet search programs based on recent Kepler findings.

Beta Pictoris is a young (12 Myr) main-sequence star surrounded by at least one planet at a distance of ~10 AU, and a dusty debris disk created by catastrophic collisions of planetesimals. We propose to make a deep observation of the 69 micron band of crystalline olivine in the debris disk of Beta Pictoris. The debris disk is resolved with HERSCHEL-PACS. This will enable us to study the collisional processes within the debris disk. The discovery of more than 600 exo-planets in the past two decades has shown an amazing diversity in the properties of planetary systems. The origin of this diversity and the way the solar system fits in must be understood by studying young systems in which planet formation is ongoing, and by comparing the properties of these young systems with the historic records of the formation of the solar system as recorded in e.g. asteroids and comets. Beta Pictoris is a unique object for this, since it is bright and it still shows spectral features since it is young enough to still have small grains. Previous studies have already shown that the crystalline olivine material in Beta Pictoris is very similar to that in our own Solar System. Using the integral-field-spectrometer PACS we will be able to look at the 69 micron band of crystalline olivine at the position where the material is created and further out in the disk. This enables us to follow the complete dust creation, avalanche and blow out processes in the disk. Understanding these collisional processes is very important since they strongly effect the properties, formation and evolution of planetary systems.

Among all species detected in the diffuse interstellar medium, CH+ and SH+ are unique. Since their main production pathways are highly endo-energetic, their large observed abundances are likely the signature of the dissipation of turbulence. In addition, since the energies involved in their formation differ by more than a factor of 2, a comparative analysis of CH+ and SH+ provides essential clues on the nature of the dynamical processes involved in turbulent dissipation.

We propose here to perform sensitive Herschel/HIFI observations of 13CH+ and SH+ in absorption towards 5 background dust continuum sources located in the inner Galaxy : W49N, G34, W51, DR21(OH), and W33A. Each line-of-sight samples kiloparsecs of diffuse interstellar matter. Given the sensitivity and resolution of HIFI, we propose to reach a signal/noise ratio of about 300 in order to analyze the velocity structure of individual clouds along the sightlines. This project has two main goals : (1) characterize the kinematic signatures of the 13CH+ and SH+ absorption lines and compare them, statistically, to those of molecular species whose formation routes are less (or not) endothermic and (2) confront the 13CH+ and SH+ abundances to model predictions in order to directly derive for the first time the turbulent dissipation rate and the ion-neutral velocity drift driving dissipation in individual diffuse clouds.

We propose to determine the brown dwarf disc fraction at ages of ~30-50 Myr. A comparison of the disc frequencies for stars and brown dwarfs shows very different trends with age. For the solar-type stars, optically thick primordial discs are virtually non-existent by an age of ~10 Myr. At ages >10 Myr, the inner disc material is significantly dissipated, and the discs have made a transition to the debris phase. In comparison, brown dwarf discs at ~10 Myr exhibit strong excess emission in the Spitzer/IRS 5-35µm spectrum, and also show strong excesses at Spitzer 70µm. The mid-infrared colors for these ~10 Myr old discs are found to be similar to the young optically thick discs in the ∼3 Myr old σ Orionis cluster, which indicates that these are still in their primordial phase. Thus no clear transition from a primordial to a debris phase is observed for the brown dwarf discs even at ∼10 Myr ages, unlike the higher mass stars. Furthermore, we find an increase in the brown dwarf disc frequency by a factor of ~2 between 5 and 10 Myr. We propose to observe with Herschel/PACS a sample of all spectroscopically confirmed brown dwarfs in clusters at ages of ∼30-50 Myr. At present, PACS is the only instrument with the required high sensitivities to observe brown dwarf discs at these ages. Obtaining data for brown dwarfs at ages older than 10 Myr will be important to map the evolution of brown dwarf discs over a wider age range, and to determine if the brown dwarf disc decay time scale is longer than that observed for the earlier-type stars.

We propose to measure with PACS and SPIRE the broadband fluxes of two partially overlapping classes of nearby main sequence stars. Each star possesses one or both of the following characteristics: (a) it is a member of a known nearby, young, moving group, and (b) it is known to have orbiting cool dust, but the dust has been seen at only one wavelength in the far-infrared -- either with IRAS at 60 microns or with Spitzer/MIPS at 70 microns – or only in the mid-IR with MIPS at 24 microns or with Spitzer/IRS. Therefore both the quantity and temperature of the dust particles are highly uncertain. Scientific motivation for the proposed observations include (1) improvement of our understanding of properties of debris disks at young main sequence stars, (2) provision of a set of relatively bright debris disks for study with ALMA, (3) provision of knowledge of the dust properties for stars with companions, regardless of whether the companion is stellar or planetary; in the case of planetary companions, many of our proposed Herschel target stars will be observed with the extreme adaptive optics systems SPHERE and/or GPI.

We propose to observe with Herschel PACS a sample of 64 candidate transitional disks around young stars with the goal of characterising their disk geometry and relate it to the physical processes ruling disk evolution. The defining characteristic of transitional disks is a reduced opacity in the inner disk, indicating the onset of the disk dissipation phase and thought to represent an intermediate evolutionary state between primordial and debris disks. They constitute the last stage where gas and dust are available to form planets, and therefore their study is of extreme value in understanding planet formation including the formation of our own Solar System.

The sample of candidate transitional disks we propose to observe has been selected from a compilation of all the Class II young stellar objects members of nearby young clusters and associations, with known spectral types and spectral energy distributions complete up to the mid-IR. Our survey will greatly enrich the Herschel archive by extending current observations of transitional disks to a larger range of stellar masses, ages, and environments, as well as in sensitivity.

Using PACS photometry we aim at characterising the disk structure and geometry for this large sample of transitional disks, to study possible correlations of the disk parameters with their host star and environment. By combining Herschel data with complementary diagnostics (accretion rates, dust masses, multiplicity) we will determine the likely causes for disk clearing, to ultimately learn about the processes of disk evolution leading to planet formation.

This proposal is the last chance to acquire the far-IR information needed to fully exploit the scientific potential of our sample of candidate transitional disks in the coming decades. These objects are central to the understanding of disk evolution and the earliest stages of planet formation, and therefore the observations we propose have a high legacy value.

Several evidences tell us that the first stages of low mass star formation are very violent, characterized by, among other phenomena, an intense irradiation of energetic (MeV) particles. The goal of this proposal is to search for signs of MeV particle irradiation in a sample of low to intermediate mass Class 0 protostars. At this end, we propose to observe a selected list of high J HCO+ and N2H+ lines in a selected sample of sources. Based on the observations obtained within the KP CHESS, we estimate a total observing time of 20.5 hours.

Jet-driven bowshocks seem to be rather ubiquitous in star-forming regions. If the large-scale bow is commonly observed and its kinematics, the actual engine of the outflow, the Mach disk region where the gas is accelerated, has never been detected until now.

Recently, we have found observational evidence of the long-searched engine of outflows in the giant molecular bowshock TMC1B1 together with the driving jet, in Taurus (d=140 pc).

which allows Herschel to resolve the cooling region of the shock. We propose to use Herschel to investigate the dynamics and physical structure of TMC1B1, a potential benchmark for jet-driven bowshocks studies.

We propose to obtain PACS C II 157.7 micon line spectra of 10 bright debris disks around dusty, A-type stars (with 70 micron fluxes >0.4 Jy) that are expected to be gas-rich if circumstellar gas in debris disks is generated via collisinal vaporization and/or photo desorption. C II is expected to be the dominant cooling line in debris disks. The high luminosity and UV flux of A-type stars is expected to efficiently produce second-generation gas. We plan to (1) constrain directly the gas:dust ratio in debris disks, (2) test models for the production of second-generation gas from circumstellar dust, and (3) extrapolate the composition of undetected parent bodies. Since the C II line emission from debris disks is relatively faint, PACS is required to conduct these observations

As part of the GT Herschel Program CHESS we detected for the first time hydrogen chlorine in a protostellar shock, L1157-B1 (Codella et al. 2011). One of the most surprising results of this work was the lack of enhancement in the abundance of HCl with respect to dense interstellar clouds, implying that HCl is not enhanced by the passage of a shock. This means that either chlorine is not sputtered during the passage of the shock (unlikely as Si is sputtered) or that HCl is not the main reservoir of clorine in shocked regions (unlike in dense interstellar clouds). In this proposal we propose to observe HCl in a sample of shocked regions in order to determine whether this result is unique to L1157-B1. We stress that given the weakness of the HCl emission in shocks and the strong atmospheric water absorption at the requested frequency (626 GHz), the present experiment cannot be reasonably performed from ground, making of Herschel OT2 the last chance to reach the present goals.

We propose to use the Herschel telescope in the unique SPIRE/PACS parallel mode configuration to completely map the California Molecular Cloud in five photometric bands to the confusion limit at SPIRE submillimeter wavelengths. At a distance of 450 pc the California cloud rivals the famous Orion A cloud as the largest and most massive GMC in the solar neighborhood. However the California Molecular Cloud contains more than an order of magnitude fewer YSOs than Orion and is characterized by a star formation rate that is an order of magnitude lower than that in Orion. It is thus an ideal laboratory for studying the physical conditions that give rise to low rates of star formation in GMCs and thus for ultimately determining the physical factors that control the star formation rate in molecular gas, critical information required for understanding galaxy formation as well as star formation. The specific goals of this experiment are to: 1) identify and characterize the dense core population, 2) construct the core mass function (CMF) of the cloud, 3) obtain a more complete and accurate census of the YSO population and thus star formation rate in the cloud, and 4) accurately determine the nature and evolutionary status of the individual YSOs in the cloud via modeling of their SEDs. For this purpose the Herschel data will be combined with ancillary ground-based and space-based (Spitzer) photometric measurements following a method we successfully tested in a previous investigation of the natures of the NGC 2264 and IC 348 YSO populations. The proposed Herschel observations will be part of a coordinated, multi-wavelength campaign modelled on our highly successful study of the Pipe Nebula and will provide results that will constitute an important complement to those Herschel programs studying molecular clouds with rich star formation activity. So far, only about half of the California cloud is covered by planned Herschel observations, and we thus propose to complement and double the coverage of existing programs.

Due to a dramatic increase in gas-phase abundance above temperatures of 100 K, water emission illuminates the important 'milestones' of star formation. Gravitational collapse, accretion shocks, protostellar heating of envelopes and disks, and the injection and motion of outflows into the protostellar envelope all glow in water. At the same time, water in absorption probes the conditions of the cold gas. Determination of water abundance throughout the envelope allows us to place strong constraints on the the physical structure of the envelope and energy transfer occurring within it.

Analysis of H2O and H2018O transitions observed with HIFI towards intermediate mass Young Stellar Objects have shown that, contrary to expectations, the ground state H2-18O line (547.676 GHz) does not trace the warm inner envelope. Test observations towards two of our sources have confirmed model predictions that the higher excitation line at 1095.627 GHz can be used to probe the warm inner envelope and hot core.

Following this result, we propose to observe the remaining intermediate mass YSOs on our source list. We request 12.3 hours to perform HIFI DBS observations in band 4b in order that we may determine the water abundance in the inner regions of these proto-stellar envelopes.

Intermediate mass YSOs are studied as part of the WISH KP. We find our source sample is too limited to identify properties associated with stellar evolution. With this proposal we ask for time to observe two more intermediate mass YSOs with HIFI and PACS.

When looking at line profiles among or source set a confused picture appears. NGC 7129 FIRS 2 and LDN 1641 are both Class 0 YSOs but have very different line profiles. Similarly, the Vela sources are both Class I sources and even have almost the same bolometric luminosity but display very different spectra. It is noteworthy that line profiles of the Class 0 NGC 7129 FIRS 2 are very similar to the line profiles of the Class I Vela IRS 17. Furthermore, the most evolved source, AFGL 490, is most similar, albeit brighter, to one of the least evolved sources, LDN 1641.

We require more observations in order to assess if there is any relation in line profile with evolutionary state. We ask for time to observe the Class 0 intermediate YSO, Cep E-mm, and the Class I/II sources, LkHa 224.

The environment in which a star forms can potentially have a significant effect on the final planetary system that forms around it. We have recently carried out a WISE survey of the nearby, rich, young alpha Per cluster, a cluster essentially not observed with the Spitzer Space Telescope. Our findings suggest that this cluster is deficient in debris disks relative to other clusters in the same age range. We propose to use Herschel/PACS observations of WISE-detected alpha Per debris disks to determine if their distribution in semimajor axes is consistent with dynamical interactions as a principal cause of the low alpha Per debris disk fraction.

A major breakthrough in addressing the connection between disks and planets occurred in 2008 with the Spitzer Space Telescope discovery of a forest of mid-infrared emission lines of water and other molecules emitted by a high percentage of protolanetary disks around young, low-mass stars. These molecular lines reflect the physical and chemical state of the disk, and can be used in concert with disk models to study disk physical and chemical diversity in greater detail than ever before. In particular, our team is mapping the distribution of water vapor, to determine where and when planetary cores condense, and searching for the reason behind observed chemical variations between disks. A major, but not insurmountable, difficulty in the interpretation of the molecular emission from disks is the significant degree of degeneracy in disk models. The way around this difficulty is to obtain detailed multi-wavelength datasets. The far-IR region is especially crucial, as the dust here transitions from optically thick to thin, and emission depends sensitively on the temperature and density structure of the dust. We therefore propose here to complete the census of PACS photometry for emission-rich disks.

We propose to use HIFI to observe resolved CO rotational line emission from a newly-identified class of disks --- the ``disk wind'' sources. These disks have emerged as a possible link between disks with envelopes and large outflows, and older, exposed and quiescent disks, and as such offer exciting potential for new discoveries. Multiple lines of evidence suggest that these disks produce significant wide-angle molecular winds, distinct from the jet-driven outflows observed in younger sources, but the detailed structure of this wind, and its launching mechanism, remain unknown. We propose here to observe resolved CO 14-13 line profiles with HIFI from 2 disk wind sources and a reference classical disk, to provide information complementary to that provided by an extensive existing multi-wavelength dataset. In particular, high-excitation CO rotational lines, like CO 14-13, probe a distinct temperature and density regime in the disk and wind, sensitive to the few-10 AU region, which cannot be otherwise probed from ground-based observatories.

We propose HIFI observations of the CII fine structure line at 158 micron (1.9THz) in 22 pointings distributed across four Galactic anomalous emission regions (the Perseus cloud, LDN 1780, LDN 675 and LDN 1111). The currently favoured explanation for the observed anomalous microwave emission is that of electric dipole radiation from rapidly rotating small dust grains (PAHs and/or VSGs), commonly referred to as spinning dust. Although this hypothesis predicts that the source of the excess emission is due to dust, the small dust grains are sensitive to the ionisation state of the gas, and hence the spinning dust models have a dependancy on the abundance of the major gas ions. CII observations will enable us to investigate this dependancy, and combining these observations with the available mid- to far-IR observations will permit a complete analysis of the role of both the dust and gas in regions of anomalous emission. We request a total of 14.9 hrs of HIFI observing time.

Dust in debris disks is produced by colliding or evaporating planetesimals, the remnant of the planet formation process. Warm dust disks, known by their emission at =<24 mic, are rare (4% of FGK main-sequence stars), and specially interesting because they trace material in the region likely to host terrestrial planets, where the dust has very short dynamical lifetimes. Dust in this region comes from very recent asteroidal collisions, migrating Kuiper Belt planetesimals, or migrating dust.

NASA's Kepler mission has just released a list of 1235 candidate transiting planets, and in parallel, the Wide-Field Infrared Survey Explorer (WISE) has just completed a sensitive all-sky mapping in the 3.4, 4.6, 12, and 22 micron bands. By cross-identifying the WISE sources with Kepler candidates as well as with other transiting planetary systems we have identified 21 transiting planet hosts with previously unknown warm debris disks.

We propose Herschel/PACS 100 and 160 micron photometry of this sample, to determine whether the warm dust in these systems represents stochastic outbursts of local dust production, or simply the Wien side of emission from a cold outer dust belt. These data will allow us to put constraints in the dust temperature and infrared luminosity of these systems, allowing them to be understood in the context of other debris disks and disk evolution theory.

This program represents a unique opportunity to exploit the synergy between three great space facilities: Herschel, Kepler, and WISE. The transiting planet sample hosts will remain among the most studied group of stars for the years to come, and our knowledge of their planetary architecture will remain incomplete if we do not understand the characteristics of their debris disks.

Recent observations of protoplanetary disks with Herschel have revealed the presence of high-J CO lines. State-of-the-art disk models predicts that this emission arises from intermediate layers below the disk surface and above the mid-plane. These layers are shielded from the photodissociative (UV) radiation emitted by the pre-main-sequence star and are thus very important for the chemical evolution of the disk. Previous observations with PACS allows us to determine the temperature and density of the gas in these layers. The low-resolution spectra of PACS, however, does not provide direct information on the distribution of the gas. We propose follow-up observations with HIFI of the J=16-15 CO line previously detected with PACS in 8 disks. The high-spectral resolution of HIFI will allow us to directly measure the radial distribution of the emitting gas. This modest (14 hours) HIFI proposal will complement the previous PACS observations allowing to fully characterize the properties of the warm gas (temperature, density and radial distribution). The second goal of this project is to address the vertical temperature gradient inside the disk. This will be achieved by comparing the HIFI observation of CO J=16-15 line to spectrally-resolved ro-vibrational and low-J CO emission lines observed from the ground. For this we will implement thermo-chemical disk models developed in our group. We also propose follow-up HIFI observations of the strong [CII] emission detected with PACS in three protoplanetary disks. According to disk models this line is expected to emerge from the ionised disk surface of the disk and is linked to the CO chemistry (photodissociation). However, the measured line flux in HD 100546, HD 97048 and IRS 48 is high and might not all come from the disk but rather from an outflow or a remnant envelope. HIFI will allow to resolve to resolve the velocity profile of the line and in turn to disentangle its origin.

Stars form in molecular cloud cores, cold and dense regions enshrouded by dust. The initiation of this process is among the least understood steps of star formation. High!resolution heterodyne spectroscopy provides invaluable information about the physical conditions (density, temperature), kinematics (infall, outflows), and chemistry of these regions. Classical molecular tracers, such CO, CS, and many other abundant gas!phase species, have been shown to freeze out onto dust grain mantles in pre!stellar cores. However, N!bearing species, in particular ammonia, are much less affected by depletion and are observed to stay in the gas phase at densities in excess of 1e6 cm!3. The molecular freeze!out has important consequences for the chemistry of dense gas. In particular, the depletion of abundant gas!phase species with heavy atoms drives up abundances of deuterated H3+ isotopologues, which in turn results in spectacular deuteration levels of molecules that do remain in the gas phase. Consequently, lines of deuterated N!bearing species, in particular the fundamental lines of ammonia isotopologues, having very high critical densities, are optimum tracers of innermost regions of dense cores. We propose to study the morphology, density structure and kinematics of cold and dense cloud cores, by mapping the spatial distribution of ammonia isotopologues in isolated dense pre!stellar cores using Herschel/HIFI. These observations provide optimum probes of the onset of star formation, as well as the physical processes that control gas!grain interaction, freeze!out, mantle ejection and deuteration. The sensitive, high!resolution spectra acquired within this program will be analyzed using sophisticated radiative transfer models and compared with outputs of state!of!the!art 3D MHD simulations and chemical models developed by the members of our team.

Using HIFI, we will observe three rotational transitions of water vapor, all predicted to be strong submillimeter masers, toward the massive star-forming regions W49N and W51 (Main); and toward the oxygen-rich evolved stars VY CMa and U Her. The target transitions are the 5(23) - 4(41), 5(24) - 3(31), and 6(34) - 5(41) pure rotational lines of water at 621, 970, and 1158 GHz. In combination with maser transitions of lower frequency that can be observed from the ground, the proposed observations will constrain the conditions of gas temperature, gas density, and IR radiation field within the maser-emitting region, providing important constraints upon the maser pumping mechanism. In the case of the star-forming interstellar regions, the proposed observations will also constrain the nature of the shock waves that power the maser emission.

Debris disks trace the collisional breakdown of asteroid and comet parent bodies orbiting nearby main sequence stars. Debris disks are typically cold analogs of our Kuiper belt with emission peaking near 70 microns wavelength. However, a relatively small number of warm disks are known with emission at 22 - 24 microns. These systems are especially interesting because they trace dust in the region likely to host terrestrial planets, where the dust has a short dynamical lifetimes. They also tend to be young systems aged < 1 Gyr. This knowledge of warm debris disks - extrasolar analogs to our solar system's Zodiacal cloud - is based on the 25 year old IRAS survey and observations of selected targets with ISO and Spitzer.

The Wide-Field Infrared Survey Explorer (WISE) has recently completed new, sensitive all-sky mapping in the 3.3, 4.6, 12, and 22 micron bands. Association of the WISE sources to Hipparcos and Tycho stars has led to the identification of 61 nearby main sequence A stars with robustly detected warm 22 micron excesses not previously known. To determine whether these systems represent outbursts of asteroidal dust production (such as in the HD 69830 system), or simply the Wien side of emission from a cold outer dust belt, photometry at longer wavelengths is needed. We propose Herschel/PACS 70 and 160 micron photometry of this unbiased sample of new A star debris disks. These data will allow us to fully characterize the dust temperature and infrared luminosity of these systems, allowing them to be understood in the context of other debris disks and disk evolution theory. Herschel OT1 observations of FGKM stars from this survey show a 90% detection rate for 70 micron excess emission. The results from these combined samples will strongly constrain our picture of the collisional history of inner planetary systems.

The largest dust grains dominate the total dust mass, as well as the observed emission in the far-infrared (FIR) domain. They contribute to the efficient cooling in the FIR and submillimeter/millimeter (submm/mm) wavelengths, essential for the condensation of the ISM and the star formation process. Understanding the variations in dust emissivity is of primary importance, because they directly affect the accuracy of any mass determination using the Herschel photometric data. They are also extremely interesting in the prospect of understanding dust physics. For long time, the lack of data in the submm domain has induced to model the submm dust emission by a modified black-body, characterized by the mean dust temperature and a temperature and wavelength independent spectral index. However, analyses of recent data have shown a significant flattening of the dust emission spectrum in the submm/mm domain, for temperatures around 20 K. Emissivity variations also seem to be temperature-dependent. Two main models of the FIR/submm emission have been proposed to explain astrophysical observations, leading to different estimates of the interstellar medium characteristics. The present proposal aims at obtaining Herschel low resolution spectroscopic data towards the warmest regions of the ISM, in order to measure precisely their dust continuum emission. Indeed, dust processes occuring in warm/hot environments are poorly known. This unique combination of PACS and SPIRE spectroscopy for a sample of 7 compact/ultra-compact HII regions, accounting for 15.4h observing time, will allow us to efficently discrimate between possible dust models.

While Herschel observations of water vapour in warm regions (T_gas >> 100 K) driven by energetic processes (outfows, shocks, hot cores, etc.) have confirmed large abundances of water vapour (~10^-5), the inferred gas phase H2O abundance in dark clouds is very low, ~10^-10. A detailed balance between freeze-out, ice-mantle desorption and gas-phase chemistry is required to explain this orders-of-magnitude abundance difference.

The Horsehead nebula is particularly well-suited to investigate grain surface chemistry in a UV irradiated environment. Its relatively low UV illumination (~60 in Draine units) implies low dust grain temperatures, from T_dust=30K in the PDR to T_dust=20K deeper inside the cloud. Therefore, the release of the grain mantle products into the gas phase, water vapour in particular, is dominated by UV-induced photo-desorption and not by thermal evaporation (as in other warm PDRs such as the Orion Bar). Besides, owing to its simple edge-on geometry, the Horsehead is very close to the prototypical kind of source needed to serve as model benchmark.

A relatively low water vapour beam-averaged abundances (~5x10^-9) was derived from a single position of the o-H2O ground-state line towards the so-called "IR peak" of the Horsehead PDR. However a detailed comparison with sophisticated PDR models including gas and grain chemistry is not possible due to our complete ignorance about the true H2O spatial distribution as one moves from the UV-illuminated cloud surface to the inner shielded cloud. We propose here to map with HIFI the o-H2O 557 GHz line on a cut across the PDR front, and extract the spatial information required to constrain the role of water freeze-out and water ice photodesorption as a function of cloud depth.

We propose to use Herschel HIFI and SPIRE to observe emission lines of water and CO in a low-mass Class 0 protostar, HOPS 87 (a.k.a. OMC-3 MMS 6N), for which we have characterized the water emission spectrum extensively with Spitzer-IRS and Herschel-PACS. HOPS 87 is the most luminous source of water emission lines found in a survey of low-mass YSOs, but has very little other emission that could be taken as evidence of a high-velocity outflow; if it truly lacks such an outflow at present it provides a rare opportunity to examine emission from the infalling envelope and potentially the envelope-disk accretion shock. With HIFI spectra we will determine whether or not the water emission arises in a high-velocity outflow, and detect separately the kinematic signatures of the warm inner envelope, the outflow-cavity walls, and perhaps the envelope-disk accretion flow. Confirmation of the detection of dense water in the disk accretion flow, which has been suggested as the origin of the mid-infrared (20-40~\micron ) water emission, would be the first unambiguous detection of this flow and is a major goal of this proposal. With SPIRE spectra we will complete our Spitzer-IRS and Herschel-PACS census of water and CO emission in this object, thereby obtaining a particularly complete and detailed account of physical conditions in the HOPS 87 envelope.

The center of the Milky Way harbors a now dormant massive black hole (Sgr A*). Over the years evidence has mounted that Sgr A* released an energetic X-ray flare nearly 100 years ago. The strongest evidence for this is the detection of reflected X-ray emission towards molecular clouds in the central regions of the galaxy. We believe that we have directed direct evidence of the effects of this flare due to the presence of warm (excitation termperature ~ 600-800 K) H3O+ in the envelope of the Sgr B2 molecular cloud. These observations were obtained as part of the HEXOS key program and in all we have detected H3O+ J,K = 1,1 through 11,11 each in absorption. These are the inversion transitions that lie at the bottom of a given K ladder. For J,K > 3 the transitions cannot be be excited by conventional collisional excitation or by radiative pumping. Instead our model strongly favors that the rotationally warm H3O+ is the result of formation pumping due to the strong impinging X-ray flux, potentially from Sgr A*. We propose to follow up this fantastic result with a small search for rotationally warm H3O+ absorption towards other galactic center molecular clouds that are strong continuum sources and are in close proximity to Sgr A*. This proposal follows a very interesting molecular astrophysical puzzle that may be a direct link to activity from the central engine of our galaxy.

The study of the transition from gas−rich protoplanetary disk to gas−poor debris disk is crucial to constrain the planetary formation mechanisms. Although it is a key parameter for big gaseous planet formation, the evolution of the gas−to−dust ratio with time and star properties is not yet known. One of the first steps to observationally constrain it is to determine independently the gas mass and the dust mass of disks. The dust content, determined from continuum emission, is better known than the gas content. As molecular hydrogen is not observable at the low temperatures of disks, the gas mass is usually derived from CO observation. However, CO may not be always the main carbon reservoir: it should freeze on grain mantles in the cold mid−plane of T Tauri disks, and be photodissociated in the upper layers by the UV field, leading to CI and CII, especially in disks surrounding A stars. We propose here to characterize the gaseous Carbon content in three disks (CQ Tau, MWC 758 and MWC 480) using the three main C carriers: CO, CI and C+. Previous CO observations indicates warm disks (the temperature being well above the CO freeze−out temperature). Two of them, CQ Tau and MWC 758, have very low CO content and may be in the transition stage between gas−rich and gas poor disks. A low CI content was also found for CQ Tau using APEX. We propose to take advantage of sensitivity of Hershel at 1900 GHz (157 um) and high spectral resolution provided by the HIFI instrument to observe C+ in these disks.

This proposal was ranked B for the OT1 period. We resubmit an updated version.

Seventy years after its discovery in the diffuse interstellar medium, the origin of the CH+ cation is still elusive. Herschel/HIFI offers a unique opportunity to disclose the underlying gas dynamics at the origin of CH+ in the diffuse medium by allowing high sensitivity and high spectral resolution observations of the CH+(J=1-0) transition, unreachable from the ground: it is the only instrument, for the decades to come, able to bring a completely new look at this resilient puzzle.

The abundant CH+ ion is not only a sensitive tracer of the most tenuous phases of the interstellar medium but it appears as a specific tracer of turbulent dissipation, because its formation route is highly endoenergic. We propose absorption spectroscopy observations of the CH+ J=1-0 line, against 7 background dust continuum sources, bright enough to allow the sample Galactic environments with highly different turbulent dissipation rates. We take advantage of the high opacity of the CH+(1-0) transition to search for CH+ in more diffuse components than previously observed: in the high-latitude diffuse medium, in gas out of the Galactic disk and in the outer Galaxy. The unknown H2 molecular fraction of these poorly explored parts of the diffuse Galactic component will be inferred from the CH absorption lines.

The primarily goal of this project is the comparison of the CH+ abundances with model predictions, in which turbulent dissipation proceeds either in low-velocity shocks or intense velocity-shears. Another goal is testing the possibility that CH+ forms at the turbulent interface between the two thermally stable phases of the interstellar medium. Last, as HF, CH+ is a potential sensitive tracer of diffuse molecular matter in the early universe. Understanding its origin and the dissipative processes that it traces will shed a new light on galaxy formation and evolution.

Photon Dominated Regions (PDRs), where physics and chemistry are driven by FUV photons, show an extreme rich warm gas photochemistry closely related to proto-planetary disks and starburst galaxies. Spatially resolved studies of nearby PDRs are essential as they enable us to characterise the physico-chemical processes that control the regions and can serve as templates for compact systems where these process cannot be disentangled. The rotationally excited lines of CO, OH and CH+ probe the warmest PDR gas layers, providing strong constrains for the modelling of both the complex physics and chemistry driven in the presence of FUV fields. The emission of these lines have been recently connected to the presence of high-density structures (clumps or filaments). We propose to map the high-J CO, OH and CH+ lines in the Orion Bar, using fully sampled PACS maps and HIFI observations. These observations will probe the spatial thickness of the line emission layers necessary for detailed comparison with the state of the art PDR models. This will enable us to characterize the origin and excitation mechanism of these high rotational lines improving our understanding of the physics and chemistry of the warm phase in the ISM.

This proposal aims at investigating the early protostellar evolutionary phases of protostars. In addition to the study of their fundamental properties (e.g. density, temperature, infall rate, accretion rate), a major focus of this proposal is the interpretation of the more extended gas components connected to the protostar. Extended envelopes, outflow shocks and jets and PDRs originating in the outflow cavities can potentially ontribute to this complex more extended emission. The spatial discrimination between these different excitation mechamisms and the quiescent underlying gas requires the combination of spatial and spectral information on several diagnostics that span a range of physical and chemical conditions. We propose PACS full SED oversampled spectral mapping around a carefully selected sample of 7 protostars at different evolutionary stages in the Chamaeleon-Musca cloud complex. This region is particularly suited to spatially resolved studies due to its proximity. This proposal is one of the many spin-off projects with an origin in the Gould Belt Key Programme and will complement other Herschel studies of protostars.

We propose a survey of water lines toward an unbiased flux limited sample of low-mass protostars newly discovered in recent Spitzer and Herschel Gould Belt imaging surveys. Water has long been speculated to be a key molecule in the chemistry and physics of star-forming regions, but its actual role is only now starting to emerge thanks to Herschel. Initial HIFI data reveal surprisingly complex water emission profiles, which uniquely trace the different dynamical processes during the embedded phase of star formation (outflows, jets, shocks, infall, expansion). By using lines originating from different energy levels, the water abundance in the cold and warm gas can be determined as function of velocity and thus the chemical processes that shape them (gas-grain interactions, high temperature reactions). The ortho/para and HDO/H2O ratios hold important clues on the temperature history of the clouds and on the journey of water from cores to disks and planets. Combination with PACS data on water and related species (O, OH, CO) can determine the total gas cooling budget and can quantify the 'feedback' of the protostar on its surroundings in terms of UV radiation and shocks.

The unbiased WILL sample allows all of these questions to be studied as function of source characteristics and protostellar evolution in a statistically significant way, thus charting the processes that shape the emerging young star and disk in the critical period from the collapse phase to the envelope dispersion stage. No other space-based heterodyne mission will be available to provide velocity resolved water lines for at least 30 years, making this program a true Herschel Gould Belt line emission legacy.

Molecular oxygen has proven to be the most elusive molecule in the interstellar medium. Despite the fact that it in theory forms easily in both warm and cold dense gas, extensive searches with SWAS, Odin and Herschel have only resulted in detections in two sources. In addition, upper limits in various astronomical environments are at levels of 1000 times less abundant than predicted by chemical models.

This situation requires either for atomic carbon to be abundant enough to suppress the O2 by CO formation, or for atomic oxygen to accrete onto grains and remain bound there. However, the binding energies of atoms to grains are highly uncertain and high abundances of OI in depleted gas have both been directly observed and inferred from observations of other molecules. A possible explanation is that OI is bound to grains by fixing (get hydrogenated to form ices) rather than sticking (van der Waals bonding to the surface potential), which will become less efficient in high density gas.

Based on this, our calculations show that molecular oxygen could be abundant in dense cores of high CO depletion. To test this theory, we propose to search a small sample of starless depletion cores for emission in the low excitation O2 line at 487.249~GHz using Herschel HIFI.

Interstellar ices are readily formed from accretion of atoms and molecules onto cold dust grains, and in dense cores the gas would be depleted in all heavy molecules were it not for the operation of some non-thermal desorption process.

Methanol molecules are only formed efficiently from hydrogenation of CO molecules accreted onto grains, but is still widely observed in cold dense clouds. This attests to the operation of desorption processes not related to the heating up of the gas from a nearby star. Proposed mechanisms for injecting the ice mantle molecules into the gas-phase includes both continuous processes, such as cosmic-ray impacts, photodesorption, or ejection upon formation, and more transient ones such as clump-clump collisions, and effects of embedded protostars influencing the chemistry through shocks or dissipation of magnetohydrodynamic (MHD) waves. The presence of distinct peaks of methanol emission at positions significantly offset from protostars, however, implies that the desorption process is indeed transient, and likely to also disrupt a major part of the ice mantles. This would lead to very high water abundances at these peaks, clearly distinguishable from what is expected from photodesorption or steady-state gas-phase chemistry.

In order to constrain the active ice desorption mechanisms in cold molecular clouds, we thus propose to use HIFI to observe the ground state transition of ortho water at three different methanol peaks: two at different distances from the Class I protostar Barnard 5 IRS1, and one in L1512, a region free from protostellar activity.

We propose Herschel dual-band PACS photometry for a unique set of 31 (B8—K0) stars that host on-going activity in the terrestrial planet zones, to probe for signatures of cold/outer planetesimal belts. We are interested in probing a fundamental question about planetary systems–is a two-belt structure like that of the solar system the most common outcome of planet formation? These young solar- and A-type have dust emission well characterized with Spitzer/IRS 5-35 micron spectroscopy, revealing dust regions similar in temperature to our asteroid belt and the interior zodiacal cloud (T∼150–200 K). Because the warm belts have a median temperature of ∼190K, slightly warmer than that expected at the snow line, we have reason to believe that there is a common grain creation mechanism operating in the inner regions of the star-disk systems. Herschel provides the observational sensitivity at PACS 70 (or 100) micron required to successfully constrain the extent of the inner/warm dust emission, or reveal the presence of an outer/colder belt of planetesimals. In summary, the PACS observations will: 1) detect the long wavelength emission of the warm/inner dust and/or establish the existence of an outer/colder planetesimal belt; 2) constrain via modeling properties of the emitting dust; e.g. charateristic temperature, minimum mass and position; 3) facilitate comparison of dust distributions across stellar spectral range; and 4) establish the overall architecture of the circumstellar dust, perhaps pointing to favorable regions where exoplanets may reside. We request 35.2 hours in PACS AORs using the mini-scan map mode for point-sources, selecting the blue (60–85 micron) filter for most (26 of 31) targets, and the green (85–125 micron) filter for 5 targets with Spitzer 70 micron detections in agreement with the short-wavelength warm-fit extrapolations.

We propose Herschel dual-band PACS photometry for a unique set of 20 stars that host on-going activity in the terrestrial planet zones and evidence of an outer/colder dust component, to continue the exploration, begun with Spitzer, of their disk structure and composition. The 20 solar- and A-type stars in this sample have combined Spitzer IRS+MIPS (5 to 70 µm) SEDs suggesting a two-ring disk architectures that mirror that of the asteroidal-Kuiper belt geometry of our own solar system. However, the extents of the outer zones are unconstrained due to the lack of data beyond 70 µm. Also, because the warm belts in our sample—across the B8 thru K0 stellar spectral range—have a median dust temperature of ∼190 K, slightly warmer than that expected at the snow line, we have reason to believe that there is a common grain creation mechanism operating in the inner regions of the star-disk systems, perhaps related to icy planetesimals in a cold outer regions. Herschel provides the observational sensitivity at PACS 100 and 160 µm required to successfully constrain the long wavelength emission of the outer/cold disks, and possibly resolve a subset of them. In summary, the PACS observations will: 1) establish the characteristic dust temperature of the outer/cold belts and constrain the minimum mass and position of the debris rings; 2) possibly resolve the spatial extend of a subset of systems; 3) advance our understanding of dust particle composition by constraining the long wavelength emission; 4) facilitate comparison of dust distributions across stellar spectral range; and 5) establish the overall architecture of the circumstellar dust, perhaps pointing to favorable regions where exoplanets may reside. We request 8.0 hours total in PACS AORs using the mini-scan map mode for point-sources, selecting the green (85–125 µm) and red (125-210 µm) filters to constrain the long wavelength emission for all targets.

The HF molecule is an excellent tracer of H2, even at low column densities where CO is photodissociated, as shown by widespread absorption in the 1--0 line at 1232 GHz seen with Herschel. We have made the surprising observation that this line appears in emission towards the Orion Bar, which is where ultraviolet radiation from the Trapezium stars hits the molecular cloud and causes heating and dissociation. Three mechanisms may cause this unusual effect: thermal excitation, which requires very high gas densities; radiative pumping by dust continuum or H2 line emission at ~2.5 microns; or chemical pumping where most HF is formed in the J=1 state. These models each predict a distinct spatial distribution of HF, which is why we hereby propose one-dimensional maps of HF in the Orion Bar and two similar regions. Combined with existing maps of CO and dust emission, the new data will constrain the density structure of molecular clouds in the low column density regime which is inaccessible to other telescopes, and thus offer fundamental insight into the physics of the interstellar medium.

Water, as a dominant form of oxygen, the most abundant element in the universe after H and He, controls the chemistry of many other species. It is a unique diagnostic of warm gas and energetic processes taking place during star formation.

We therefore propose to exploit the unique opportunity of Herschel to study water in large, statistically significant, flux limited samples of massive star forming regions detected in the recently completed ATLASGAL submm dust continuum survey of the inner Galactic plane.

In the last years, our view of massive star forming regions has dramatically changed by Galactic plane surveys covering cm to IR wavelengths. These surveys enable us for the first time to study ALL evolutionary stages of massive star formation (MSF) in an unbiased way. Water, acting as a natural filter for warm, dense gas, allows to probe the chemical and physical conditions in all of these stages close to where the massive stars are forming or just have been formed.

ATLASGAL observed submm dust continuum emission as best tracer of the earliest phases of MSF since it is directly probing the material from which the stars form. As a large unbiased survey it provide the statistical base to study the scarce and short-living protoclusters as the origin of the massive stars and the richest clusters in the Galaxy and supplies us with a legacy value sample of MSF regions for the water follow ups.

Water is typically seen with strongly increased abundances in broad line wings, providing a new, sensitive probe of shocked outflowing gas. In addition, the envelope is probed in a combination of absorption and emission with a clear jump in abundance in the warm inner regions close to the forming massive stars. Only Herschel can provide a water survey of a large sample of ATLASGAL selected sources to study water through the evolution of massive star forming regions with a statistically significant sample size.

Follow-up Herschel observations have recently confirmed the presence of a resolved debris disk around GJ 581, a nearby M star with 4 low-mass (super-Earth) planets. Debris disks around M stars are exceedingly rare (~1% detection rate in the DEBRIS survey), raising the question of whether the debris might somehow be directly related to the neighboring planets. In order to assess whether low-mass planets are strongly correlated with dusty debris or whether this is just a chance coincidence, we propose to dramatically increase the number of planet-bearing M stars observed by Herschel, from the current 3 up to a total of 20 stars. The proposed PACS 100/160 um images of 17 planet-bearing M stars will clarify whether this class of system preferentially has orbiting debris. Should any new disks be detected, the close proximity of the target M stars (~10 pc) makes them favorable candidates for resolved imaging, which may help to explain the unusual asymmetry in GJ 581's similarly resolved disk.

We propose to use second epoch PACS+SPIRE photometry of nearby star-forming regions to detect episodic accretion events onto the youngest, Class 0, protostars. It is well accepted that the bolometric luminosities of these young protostars fall at least an order of magnitude below the steady-state accretion luminosities needed for their assemblage and that as much as 90% of the total mass must be accreted during episodic events. Optical and IR monitoring of older, non-shrouded pre-main sequence stars has revealed powerful episodic events (FUors and EXors) but not until Herschel have we been able to map large enough star-forming regions to the depths necessary to perform this time-domain survey for episodic accretion onto Class 0 protostars.

The proposed 21.8 hour survey of Aquila, NGC 1333, Oph L1688, and IC 5146 will map more than 200 known Class 0 protostars, 500 Class I protostars, and thousands of pre-stellar cores. These second epoch multi-wavelength observations allow us to be sensitive to order unity variations in bolometric luminosity (and temperature) and thus while we are unlikely to observe any rare, extreme accretion events, we will be able to place constraints on the importance of more common accretion enhancements in supplying mass to the protostar. All interesting detections will become prime candidates for follow-up detection from the ground.

Our proposed Herschel program is our best chance to probe accretion variability for the youngest protostars, which are in an evolutionary stage that has not been observable in previous or ongoing variability surveys.

In the past decade, transition disks have emerged as the first possible, measurable signposts of planets that have already or are in the process of forming. Recent detections of planetary mass objects within the inner holes of two transition disks definitively link the presence of disk holes with planet formation. However, these transitional disks have so far not yet been studied much in the warm molecular gas of a few 100 K, which connects the cold bulk mass of the outer disk (probed in the sub-mm) with warm inner regions (probed in the near-IR). The structure of transition disks is typically measured from the shape of the spectral energy distribution or the spatially imaged dust. Although the gaseous disk can be more difficult to study, the structure and chemistry of gas will provide significant constraints on the prospects for the final abundances and continued growth of gas giant planets. Herschel PACS offers a unique possibility to study the mid-J to high-J lines of CO together with lines of OH and water. These lines are predicted to emerge from the inner few tens of AU. Here we propose a deep search for molecular emission in PACS spectra of 12 of the most exciting transitional disks, two of which are already approved for ALMA observations. These PACS observations provide diagnostic information on the structure and chemistry of the warm gas that is needed to constrain models of gas in transition disks and to understand the connections, if any, between the gas in the inner and outer disk.

We propose to observe nearby binary star systems to discover and characterise circumbinary debris disks. With these data we will study the effects of cluster evolution and long term stability on planet formation. The primary goal is to resolve disks, which allows an analysis of the binary and disk orbital planes and leads to conclusions about the formation and stability of the system. The secondary goal is to test whether dust resides in unstable regions, which could be the result of a dynamical instability induced by perturbations from the binary. Both goals focus on the dynamics of circumbinary debris, and provide information on planet formation and survival in binary systems.

Models that include the key radiative and chemical processes necessary to understand the emission from externally-illuminated molecular gas - so called thermo-chemical or PDR models - are now commonly invoked to account for the line flux from far-ultraviolet illuminated galactic and extragalactic molecular clouds as well as protoplanetary disk surfaces irradiated by their central stars. Whether these models are correct in general, and for water in particular, remains an open question; using present observations to test these models has proven difficult because of the complexity of the regions observed and the resulting uncertainty in many of the model input parameters. Using HIFI, we will obtain scan maps in the ground-state 1(10)-1(01) ortho-water transition at 557 GHz across the ionization front/molecular cloud interface toward two well-studied, uncomplicated regions with favorable geometry - Cepheus B and the starless dark globule DC 267.4-7.5. The proposed observations will produce measures of the gas-phase water abundance across these two atomic-to-molecular transition zones, which will be compared to the model-predicted profiles of water emission versus Av into the clouds. Because of the edge-on geometry and the absence of known embedded sources along the scan paths, the proposed observations provide the best, most controlled test of these models to date. Both regions have been successfully observed previously with SWAS, but SWAS's much larger beam size made the kind of study proposed here impossible. Neither the Herschel WISH nor PRISMAS Key Programs contains observations that come close to offering as rigorous a test of the models as constructed here. Because these observations require a space-borne telescope with both high spatial and spectral resolution, they cannot be carried out from any other observatory in the foreseeable future.

We will do sensitive PACS and SPIRE observations of the LkHa198/V376 cluster to find all young stars, determine their disk/envelope masses and the star formation rate in the cloud.

Water is a highly complementary diagnostic to the commonly used CO molecule. It has a central role in protostellar environments and in outflow shocks, being one of the main coolants and the most sensitive to local conditions. As part of the WISH key program, a survey of several H2O lines at different excitation has been performed with HIFI at two selected shock spots in the bright L1448 and L1157 outflows. These observations and their analysis have given unexpected results, that contrast with current models of water emission in shocks. However, the validity of these results needs to be checked with suited high S/N observations, allowing to remove some of the free-parameters of the line excitation modeling and to derive water abundance.

The goal of this proposal is to clarify the controversial issues raised by these previous observations by mapping with HIFI a 40 arcsec area covering two shock positions along the NGC1333-IRAS4A outflow, identified as very bright in H2O from our PACS map at 1670 GHz, in key spectral transitions of H2O and CO. These observations will provide unprecedented constraints on the physical and chemical properties of the gas associated with the water emission, as a function of velocity, and on the properties of the shock at the origin of the emission. In particular, mapping the H2O lines will allow us to remove the uncertainty originated by the largely different beams of the observed transitions. The CO(16-15) will be also observed: this line comes from the same high excitation gas as that traced by H2O and thus will provide a tool to derive an H2O/CO abundance ratio much more reliable than what is obtained with the low-J CO transitions observed from ground.

We point out that it is crucial to solve the issue of water excitation in shocks before the end of the Herschel mission, in order to correctly interpret all the data acquired on H2O in outflows by Herschel and provide reliable constraints on water abundances and shock dynamics.

We propose to obtain a contiguous 5.3 square degree square map of the extended HII region W80 using PACS and SPIRE. Contained in this field of view are the little studied North American and Pelican nebulae, and a dark molecular cloud region referred to as the Gulf of Mexico. This region has not been globally mapped by Herschel. The distance to W80 (and regions therein) is about 600 pc making it the next nearest region similar to Orion. 2MASS extinction mapping reveals Av>5 mag over most of W80, and cores in several areas exceed 30 mag. Spitzer IRAC and MIPS have observed this entire complex, yielding catalogues of hundreds of potential YSOs. We have conducted a wide-field H2 2.12 micron partial survey for shocks and outflows and have discovered dozens of highly embedded energetic protostellar outflows and jets distributed over the cloud complexes. The region rivals NGC 1333 known to harbor the highest concentration outflow sources. The O-stars that produce the ionizing UV radiation and these new young, accreting sources are responsible for the intra-cloud dispersal and the triggering of star formation in surrounding regions. Herschel photometry at 5 bands (70, 160, 250, 350, and 500 microns) are required to complete the measurement of the SEDs thereby allowing classification, measure the temperature and masses of the disks, and to better define the extended structure and morphology of the intra-cloud medium, including IRDCs, pillars, and filaments. Herschel is vastly superior to mapping large scale structure of the cold dust, warm edges, and hot dust associated with PDRs, compared with mm-surveys (eg., ATLASGAL and BGPS) as these latter surveys tend to spatially filter out large scale structure >7' in their data processing. Herschel will provide the essential high angular resolution and sensitivity data needed to quantify each SED and to map the morphology of the complexes.

The interstellar medium (ISM) is mainly comprised of ionized, neutral atomic and molecular gas. One of the most important constituents of these phases is carbon in its ionized/neutral/molecular form (C^+, C^0 and CO). However, a coherent analysis of the different phases at adequate resolution (Jeans length ~0.2pc) is lacking. We therefore want to re-evaluate the ISM carbon budget via observing primarily C^+ at 1.9THz, C^0 (at 492GHz), and CO(2-1) with Herschel, APEX and the IRAM 30m at high spatial resolution (11''-13'') for several infrared dark clouds (IRDCs). This proposal is a follow-up of a guaranteed time pilot study for the line of ionized carbon [CII] toward one IRDC. In this open time project we like to extend the sample to a total of five IRDCs in different environments. With the combined data of the different carbon phases we can address: (a) How do the relative abundances change with evolutionary stage? (b) Are the different phases mainly excited by internal or external radiation sources? (c) How important are the phase changes for the carbon cooling budget of the ISM? (d) Can we identify cloud formation signatures (e.g., turbulent flows)?

We propose a sensitive search towards six Galactic sources for the small negative molecular ions (anions) --- CN$^-$, CCH$^-$, OH$^-$, and SH$^-$ --- with {\it Herschel's} Heterodyne Instrument for the Far-Infrared (HIFI). The full significance of anions in astrophysics is far from understood, and molecular anions may have a much broader impact on the chemistry and physics of astronomical sources than is currently appreciated. In dark clouds and low-mass star-forming regions, reactions of molecular anions are thought to enhance the abundances of neutral polyynes and cyanopolyynes. In circumstellar shells of evolved carbon stars, anions are theorized to form by proton transfer reactions of neutral carbon chain radicals with H$^-$, as well as through reactions of atomic N with large carbon chain anions. By influencing the ambipolar diffusion rate, anions may regulate the dynamics of star formation in magnetized plasmas around collapsing molecular cloud cores. Because the abundances of anions are sensitive to electron attachment and photodetachment rates, anions can serve as direct probes of electron densities and cosmic-ray ionization and photoionization rates within interstellar clouds, provided the formation and destruction processes of anions are known. The main question we seek to address is just how widespread anions are in the Galaxy. The four anions we propose to study are structurally simple molecules, with precursors that are abundant in the interstellar gas. The observations here will provide key information on the distribution small molecular anions, which, when combined with chemical models of the observed anion abundances and their dependence on conditions within their astrophysical environments, will advance our understanding of the role of anions in the physics and chemistry ofastronomical sources.

Our science goal is to study the influence of massive star-forming　activities to the physical and chemical conditions of interstellar space. Our target region in the Carinae Nebula especially region around Eta　Carinae, where massive star clusters and molecular cloud complexes are observed and there are indication of past activities of stellar wind and current activities of star formation is observed. We use far-infrared atomic fine structure lines as a tool to study the influence of massive star to the interstellar material surrounding it. Observing area is selected from wide area spectroscopic imaging of　AKARI observations. Herschel Space Observatory will show the high angular resolution images of the selected regions with high activities. Eta Carina and their surroundings are at relatively low extinction region, and comparative study in X-ray, optical, infrared and radio observations can be done easily. Detailed observation of massive star forming region in Carina Nebula is important to understand the role of massive star-forming region in general in our galaxies and external galaxies including high extinction regions.

Infrared Dark Clouds (IRDCs) are thought to host the earliest stages of high-mass star formation, an epoch that is still poorly understood. Gound-based millimeter observations have found that many IRDCs have embedded cores, and Herschel PACS and SPIRE photometry has made it possible to image many of these very cold cores via their dust emission. We have used the Submillimeter Array (230GHz) to observed a sample of cold IRDCs that are dark even at PACS70, but which contain bright cores seen in emission in the SPIRE bands. The SMA spectral maps and the molecular chemistry suggest at least three early stages of star formation that we have tentatively modeled as reflecting three progressive temperature and evolutionary stages. Unfortunately in the youngest, coldest sources most diagnostic molecules are either frozen out onto grains or have not yet assembled. Nitrogen hydrides, however, do not suffer from depletion effects in cold, dense regions, and so offer an invaluable tool to probe the early stages. Herschel HIFI is uniquely suited to observe the key ground-state absorption lines of four nitrogen hydride species: NH, NH2, o-NH3, and p-NH3. Our chemical models show that the line ratios are sensitive measure of density, temperature, and inferred evolutionary stage. We therefore propose observations of four very cold cores in IRDCs that we have already studied with the SMA; we supplement them with two progressively warmer IRDCs for reference with only a modest increase in time. Our goal is to quantify the early evolutionary stages of IRDC cores before they form stars, and the associated chemical activity in the cloud. We will also use the results to refine our chemical models of the nitrogen hydrides under these conditions. Our team is expert in chemical modeling of dark clouds, IRDCs, millimeter and submillimeter astronomy, and Herschel HIFI data reduction and analysis.

Theoretical models of planet formation have shown that the masses of protoplanetary disks, which are dominated by gas, strongly affect the resulting planetary architectures. Expanding upon the Herschel KP "Gas in Protoplanetary Systems" (GASPS), we propose here a sensitive Herschel/PACS survey to measure the gas disk masses of a well-characterized sample of very low-mass stars/brown dwarfs (BDs). Our survey has two main goals. First, we will empirically set a limit for the largest planets that can form around BDs and thus elucidate the nature of the few planet candidates discovered around them. Second, we will combine our mass estimates with those acquired within GASPS for intermediate- and solar-masss stars to constrain how the disk mass scales with the mass of the central star. To reach these goals we will use deep PACS exposures to detect the [OI] 63 micron emission line which traces the bulk of the disk mass residing beyond tens of AU from young stars. We will use similar models to those developed within GASPS to convert [OI] line fluxes into gas masses. The sensitivity of Herschel/PACS gives us a unique opportunity to measure disk masses down to the BD regime and to provide the critical observational constraints to planet formation theories.

Until recently, debris disk identification and study has been accomplished mostly with the 30 year old IRAS all-sky survey (and small number of pointed observations by Spitzer) and it has been limited to larger cold disks. Study of warm debris disks can provide important information concerning terrestrial planet formation and evolution, however, their identification and characterization has been restriected to a very small number of discovered warm debris disks (N<10). The Wide-Field Infrared Explorer (WISE) has surveyed the entire sky at mid-IR wavelenghts, and the WISE survey provides almost 100 times better photometric sensitivity than IRAS and approximately 10 times betterpositional accuracy. Using this improved information and sophisticated target selection criteria, we have identified a complete, well-defined group of 30 nearby (d < 100 pc) Hipparcos main-sequence stars showing the indication of warm debris disks. With nine of these stars being observed as part of an existing Herschel program, we propose to observe the remaining 21 stars to complete a census of warm debris disks in the solar neighborhood. With Herschel PACS measurements at 70 and 160 micron, we can fully constrain dust temperature and dust quantity around this rare group of stars.

Although many hundreds of debris disks have been discovered over the past three decades, these stars are widely diversed in terms of ages, distances, reliabilities, levels of dust characterization, etc. Nearest debris disks are most interesting because they are brighter and larger than more distant similar debris disks. By collecting all known debris disks in the literature, we re-analyzed all debris disks (about 1800) in a homogeneous way using the state-of-the-art photosphere fitting method and including the newest available data including WISE. Out of this reanalysis, we selected 123 nearby (d<100[c) bona-fide debris disks where almost a half of them have a dust excess measurement at only one passband. To constrain dust properties for these nearby debris disks, we request to obtain 100 and 160 micron measurements with Herschel/PACS. The result of this proposed study will be a complete inventory of known debris disks within 100pc with fully constrained dust properties. Such an inventory will be an indispensable asset for any future debris disk studies with ALMA, SOFIA, SPICA, etc.

Herschel offers an unique opportunity to probe the conditions and chemical evolution in the planet formation region of disks, particularly at radii immediately beyond the snow line (~ 1 to 20 AU), the formation zone for asteroids and gas giants in the Solar system. We propose PACS spectroscopy of a small sample of T Tauri star disks in order to investigate the oxidation state of the gas at these radii, a key parameter in gas-phase chemistry and solid-state mineralogy. The proposed data will provide an important observational link between the oxidation conditions implied by known meteoritic properties and T Tauri disks as proxies for the conditions in the early solar nebula. Results from Spitzer already suggest variations in the oxidation state of the warm gas interior to the snow line, based on the observed range in the content of simple organic molecules relative to water. This could result from different efficiencies in planetesimal growth and sequestration of water ice beyond the snow line, differences potentially related to the mass of the disk. The oxidation state outside the snow line is influenced by the radial transport of water vapor and ice, settling and turbulence, and the growth of large icy bodies. The action and efficiency of these processes can leave their imprint on the C/O ratio of gas in the disk atmosphere, with predicted changes in the chemistry. We propose to carry out sensitive PACS spectroscopy of chemical signatures (CO, NH3, HCN and H2O) that can probe the oxidation state at 1-20 AU. The targets are carefully picked to sample a range in disk mass and organic disk signatures inside of the snow line. The combination of Herschel and Spitzer data will allow us to compare the chemistry interior and exterior to the snow line and to better understand the role of physical processes such as the radial migration and growth of icy bodies that affect disk chemical evolution and planet formation.

G29-38 is the prototype and brightest example of a white dwarf orbited by rocky debris from a tidally-destroyed planetary body. Because this warm debris orbits within 1 solar radius, the parent body must have originated in a more distant region. Thus, we suspect a persistent planetesimal belt at G29-38, that contains a substantial number and mass of remnant planetary bodies, as this best accounts for the larger family of disk- and metal -polluted white dwarfs. We propose Herschel PACS observations to detect cold dust from within this remnant population of minor planets. A lack of cool dust favors a scenario in which the observed warm dust resulted from the tidal destruction of a major rocky planet. The proposed observations are the best chance to detect such a cold disk around any metal-enriched white dwarf, and will provide insight into the fate of planetary systems at A- and F-type stars.

Recent studies have shown that there is a surprising amount of variability on many timescales in the mid-infrared emission of young stellar objects (YSOs). Especially on short timescales of minutes to hours, mid- and particularly far-infrared variability is currently almost entirely unexplored. While such variability is probing circumstellar disks and envelopes, it is linked to physical processes on the central object. Already the earliest evolutionary stages of YSOs are also strong X-ray emitters, and one important aspect is the heating and possible eventual dispersal of circumstellar disks due to X-ray emission. Even though very important for the understanding of planet formation, this process is poorly understood. The Herschel Space Observatory offers the last possibility for the foreseeable future to explore these processes in more detail and learn about disk heating and explore the occurrence of short-term variability. Here, we propose to do both by repeated observations of the extensively studied nearby Coronet cluster in the CrA star-forming region. Five epochs of near-simultaneous XMM-Newton and Herschel observations, each about 1.5h in duration and spaced by timescales of days to weeks, are meant to explore the short-term variability and link it to the more frequently studied variability on longer timescales. During each epoch, the cluster is mapped 18 times with Herschel. The Coronet has been chosen for having YSOs that can be detected at high S/N in short periods of time while not being too crowded for the angular resolution of both observatories. By exploring far-infrared variability on timescales of several minutes to days and weeks as well as disk heating by protostellar X-ray emission, these short observations will have a unique legacy value.

We propose to use the SPIRE-FTS to map a 8.5'x8.5' (~20pc x20pc) region around Sgr B2, the only source that allows studying a burst of star formation in the center of a galaxy (GC) with high spatial resolution even using a single dish telescope (25'' = 1 pc).

Bright high-mass star forming regions do exist in the disk of the galaxy, but the specific location of Sgr B2 in the GC (where the ambient physical conditions are markedly different compared to the disk) make it the best source to compare with unresolved extragalactic nuclei (M82, the prototype starburst galaxy is ~400 times more distant and thus 25''=400 pc).

Our SPIRE-FTS pointed observations around Sgr B2(M) core and surroundings show strong dust continuum emission as well as emission lines from 12CO and 13CO rotational ladders; [NII] and [CI] fine structure lines; emission/absorption of excited H2O and NH3, and line-of-sight absorption of a variety of light hydrides (HF, CH+, CH2, OH+, H2O+, H3O+, NH and NH2) that are difficult, if not impossible, to detect from the ground. Even far from Sgr B2 star forming cores, the expected continuum and line intensities will enable us to map tens of lines over large areas in very reasonable times.

Understanding the large scale physics and chemistry of this starburst template in the GC is of great interest as recent Herschel observations are revealing similarly rich spectra in fainter galaxies where, of course, different components overlap in the beam. The proposed spectral maps and SEDs will form a large database that will be a legacy for higher angular resolution studies of extragalactic nuclei.

We propose to observe a diverse sample of protostars with Herschel-SPIRE, selected from the DIGIT/WISH programs, to answer the key question: To what extent can we separate the system properties of a protostar (e.g. envelope/disk) from the extended properties (e.g. outflows, fast shocks)? Quantifying energetic feedback from a protostar into its surrounding environment provides a key for understanding the star formation process. Because of its simple chemistry and high abundance, CO is an ideal tracer of such feedback. We have the unique opportunity to expand a well-studied dataset of low-mass protostars with a huge range of existing observations: PACS and IRS spectroscopy, ancillary IR/optical/UV/X-ray and millimeter data, selected from the WISH/DIGIT that span a variety of bolometric luminosities and temperatures. Observations of mid-J CO lines are the missing link that we need to separate the effects of outflow from envelope emission.

Massive stars are rare and distant. Their short-lived protostellar phases are therefore difficult to study, and the processes that produce them are not well understood. The Cygnus-X complex is one of the richest known regions of star formation in the Galaxy at a distance of ~1.3 kpc, which allows it to be studied at smaller scales and less confusion than other similarly active regions that are more distant. We have conducted a Spitzer Legacy survey of the Cygnus-X region and used the data to map the distribution of Class I and II YSOs in the complex, and have begun to study the interaction between the massive young stars and clusters of low-mass YSOs. We propose to use PACS and SPIRE to complete an unbiased survey in the Cygnus-X region to detect the intermediate to high-mass young stellar objects, pre-stellar cores, and infrared dark clouds (IRDCs) and their embedded objects. The Herschel observations, in conjunction with the existing Spitzer, near-IR, and other ancillary datasets will allow us to assemble a comprehensive picture of star formation in this high mass, extremely active complex. With the Herschel data we will 1) complete the sample of massive protostars and YSOs in Cygnus-X and construct SEDs of the objects from 1 to 1200 microns, 2) use the derived luminosities and envelope masses from the sample to construct evolutionary diagrams and test high-mass star formation models, 3) analyze the population of Infrared Dark Clouds in Cygnus-X, and 4) explore the role of massive stars in triggering star formation in surrounding clouds. The data will provide a useful resource for the study of star formation for years to come.

We propose to establish the evolutionary state of Maddalena's Cloud. This region is regularly discussed as a prototype for a giant molecular cloud (GMC) in an early phase of its life. This suggestion is based on the fact that this region of about 3x10^5 M_sun is entirely devoid of embedded massive stars. Thus, this region potentially presents an ideal site to study the initial conditions for the evolution towards clouds like Orion A. This is not entirely clear, though: it has also been argued that this cloud might be at the end of its life, and is now dispersing after being "stirred up" by previous star formation. We therefore propose to execute two complementary experiments to establish the cloud's evolutionary status. Both will use wide-field parallel mode SPIRE/PACS dust emission maps. First, we will obtain the first reliable estimates for the mass of the cloud and its clumps to revise the --- presently very uncertain --- virial analysis on which suggestions for cloud dispersal are based. Second, we will search for deeply embedded young stellar objects (YSOs): if these very young (class 0-I) YSOs exist throughout the cloud, it would be hard to argue that this is a cloud in which star formation is ending. Depending on these experiments, our data will then be used to constrain the physical conditions in the early life of massive GMCs. Certainly, the properties of this cloud are unique: we only expect to find about 6 such massive clouds without O stars within 2.2kpc from sun. This is the only cloud of this sort we presently know, and so our observations will have a significant legacy value for studies of star formation.

Prestellar cores are crucial to our understanding of star formation. It is at this evolutionary stage that the stellar mass is set. If we are to understand the origin of the stellar IMF, we must therefore study the masses of the prestellar cores from which the stars are formed. There is currently a large uncertainty in the measured prestellar core mass that we obtain from far-IR and submillimetre observations. This uncertainty is caused by our inability to simultaneously determine the column density, temperature and dust emissivity index from photometric observations. Physical processes such as grain growth, or ice-mantle formation, which are affected by changes in density and temperature, will change the dust emissivity index. By simply taking a canonical value for the emissivity index, we cannot determine the correct mass for prestellar cores.

The SPIRE FTS allows us to break this degeneracy for the first time, and simultaneously measure the column density, temperature and dust emissivity index, and therefore determine accurate masses. We propose to map 16 prestellar cores with the SPIRE FTS, and hence generate accurate maps of their column density. We will map each core using the full FTS field of view. We will be able to determine the absolute value of the dust emissivity index, and also see whether it varies across each of the cores. We have selected cores in different environments in order to study the core-to-core, and cloud-to-cloud variations in the dust properties. We will be able use this information about the relation between the three measured parameters, to more accurately determine masses for a much larger sample of cores for which only photometric data are available

We propose to observe the compact but well-studied protostellar core L1251B with all Herschel instruments. L1251B harbors potentially the first XDR ever isolated (there are two strong candidates) and is the only low mass source that we have an existence of the detailed maps of ice evaporation. Therefore, we propose to observe L1251B in [N II] 205.4 micron and the ground state p-H2O lines with HIFI to study the effects by high energy photons produced through the accretion process in early evolutionary stages. This will be supplemented with PACS full SED and SPIRE FTS modes. This combined data set will confirm the potential presence of the first low mass XDR. They also will allow for the only source where Herschel can connect water vapor and water ice emission to Spitzer maps of water ice absorption on equivalent spatial scales.

Debris disks surrounding main sequence stars are analoguous to the Kuiper Belt around the Sun and are signposts for exoplanetary systems according to planet formation theory. Low-mass stars (M-stars) are challenging targets for both exoplanet searches and debris disk searches. However, they are vital for understanding planet formation in complement of higher mass stars. With Herschel, we propose to confirm and characterise two M-star candidate disks while only two others are presently known among low-mass stars.

The two M-stars, GJ842.2 and HD95650, have candidate disks from SCUBA and Spitzer observations. We propose to make PACS images that are deep enough to detect their photospheres in order to verify unambiguously position coincidence between stars and disks. This approach could not be accomplished by neither SCUBA nor Spitzer. Additionally, it is reasonable to speculate that these disks will be large enough to be resolved by PACS providing definite proof of their nature. Finally, we request SPIRE in complement to PACS to fully sample the SED of the dust emission in order to determine their fractional dust lumninosities and dust properties.

One of the key question in debris disk studies today is to understand the physics responsible for the trend apparent in their detection fractions indicating fewer debris disks around lower-mass stars. Several physical clues have been suggested; for instance, observed and theorised lack of massive gaseous planets around M-stars could reduce disk stirring and so dust production. It is vital to expand the number of known disks around M-stars to tackle this key question. By resolving two new disks and modelling their images, we shall infer the scale of the planetary systems around M-stars and be able to measure the size of the inner hole hosting planets. Asymmetries in their images would be indicative of resonances with planets. The scarcity of known disks around M-stars makes these observations crucial.

We propose to use the The Galactic center (GC) a local extragalactic laboratory to understand the chemistry and the heating mechanisms in nearby galactic nuclei. The central 30 pc region around the black hole, Sgr A*, contains all the different type of activity found in extragalactic nuclei, namely, massive stellar clusters creating large photodissociation regions (PDR), shocks, molecular clouds irradiated by strong X-rays (XDRs), and the site of Cosmic Rays (CRs) acceleration as shown by HESS. We plan to map this region with SPIRE in the high spectral resolution mode and with HIFI in selected molecular ions H$_3$O$^+$, OH$^+$, and H$_2$O$^+$ claimed to trace XDRs and/or CRs. This unique data set will provide the possibility to understand the origin of the large column densities of this hydrides found in galactic nuclei with different type of activity and the role of the PDR-XDR-CR chemistries in their formation. The SPIRE data cubes will have a huge legacy value providing the full FIR inventory of the atomic and molecular gas across the central 50 pc of the Galaxy. We stress that only the combination of the high spectral resolution of HIFI and the spatial distribution provided the proposed mapping will have the possibility to distinguish which of the different components of the molecular gas along the line of sight correspond to the ones associated with XDRs PDRs and eventually CRs acceleration sites.

Stars form from contracting molecular cores, but this process relies heavily on the ability of the core to cool. This depends on chemical composition and could therefore lead to different outcomes at low metallicity. However, most of what we know about star formation is derived from studies of Galactic YSOs. Herschel provides the unmissable opportunity to extend such analysis to the low-metallicity environments of the Large and Small Magellanic Clouds (LMC and SMC), by observing the main cooling lines: fine-structure lines of oxygen and carbon, and rotational transitions of abundant molecules.

Our Spitzer Legacy Programs (SAGE; SAGE-SMC) and Herschel Key Program (HERITAGE) identified 1000s of young stellar objects (YSOs), in both Clouds. Follow-up spectroscopy (Spitzer-IRS and ESO/VLT) provided unique insight into the abundances of ices in Magellanic YSOs, revealing differences in the composition of circumstellar material at lower metallicity. Since the gas and ice phase chemistry is inextricably linked, this opens the possibility of significant variations to gas-phase abundances. Such differences could imply changes to cooling and heating rates, and consequently different star formation timescales and efficiencies.

To investigate the role of metallicity we will observe a sample of embedded massive Magellanic YSOs. We will use PACS and SPIRE FTS spectrographs to measure the strengths of key gas-phase cooling species ([OI], [OIII], [CII], H2O, CO, OH), in order to estimate temperature, density, ionization state and abundances. These observations will enable us to characterise the gas and constrain the cooling budget of the YSO envelopes. Together with our ice column density measurements, the Herschel observations are crucial to investigate how grain-surface reactions change the chemical make-up of the gas.

By comparing the SMC and LMC, and Galactic YSO samples we will assess how the chemistry, and consequently the ability of the YSO envelopes to cool, differ at sub-solar metallicity.

Advances in understanding planet formation and evolution can be gained from studying how frequently debris disks form and how they interact in different environments over time. While field stars near Earth enable small quantities of dust to be detected, the nearest rich open clusters -- with their well constrained ages -- enable one to infer how debris disk characteristics evolve with time as a function of spectral type and birth environment. Located ~172 pc from Earth, the ~60 Myr old Alpha Perseus cluster is the only substantial and nearby young open cluster or moving group that was not targeted by the Spitzer Space Telescope, yet its richness provides an excellent laboratory to address fundamental, debris disk-related, questions. Recently we identified a dozen or so Alpha Per members to have mid-IR excess based on the published WISE catalog. Previous studies of debris disks have demonstrated that significantly more stars have dominant excess emission at 60 micron than at mid-IR wavelengths, implying the potential presence of a large population of stars with cold debris disks -- analogous to the Sun's Edgeworth-Kuiper Belt -- in Alpha Per. We propose to observe 97 early-type members of Alpha Per with PACS at 70 and 160 microns; these will provide far-IR photometry for a complete sample of known Alpha Per A- and F-type stars.

Despite of all theoretical speculations and various observational constraints, the nature of the dark matter in the outer Galaxy is still unknown. Herschel/HIFI offers the unique opportunity to detect or set a significant upper limit to a potential component of baryonic matter in the form of cold gas, which is molecular in hydrogen, but does not form CO. Such gas can be potentially be traced through [CII] 150 um and HF J=1-0 absorption against continuum background sources. We propose a set of 7 the brightest outer Galaxy dust continuum sources, for which we will determine the positions of peak emission by PACS mapping. Deep integrations in [CII] and HF towards the 4 brightest peaks in these sources will potentially detect a cold gas component and will, in any case, give significant upper limits to its column density.

The initial conditions of massive star and star cluster formation are likely buried in the densest, coldest and most obscured regions of giant molecular clouds (GMCs). We propose to use this obscuration to our advantage by carrying out sensitive, high angular resolution 70, 100, and 160 micron PACS imaging of 10 Mid-Infrared Dark Clouds (IRDCs). Building on our experience of Mid-IR extinction (MIREX) mapping, we will apply a new analysis method of Far-Infrared extinction (FIREX) mapping to derive estimates of the mass surface densities and temperatures of massive starless cores and clumps. Compared to the 8 micron-derived MIREX maps, 70 micron-derived FIREX maps will be able to probe to at least 4 times higher values of mass surface density, into a regime >1 g/cm^2, which some theories predict is a necessary condition for massive stars to form. The high angular resolution 100 micron images are crucial for disentangling temperature variations in the IRDCs, which can mimic 70 micron absorption. This analysis will be aided by comparing with the lower resolution 160 micron images and Hi-GAL SPIRE data. It is possible that absorption at even 100 microns will be seen, picking out the very densest, coldest regions.

We note that while 70 micron (but not the crucial 100 micron) data exist for these IRDCs from the Hi-GAL survey, our proposed observations will have much improved angular resolution and flux sensitivity because of the use of a slower scanning speed. This is important to probe the highest mass surface density cores and clumps, which we know contain sub-structure down to scales at least as small as the resolution of the proposed images, ~5 arcseconds.

This project requires the stable FIR photometry that is only possible with Herschel PACS. At the same time unique science questions, resulting from probing the most extreme mass surface density regions yet studied by extinction mapping, can be carried out with a modest amount of observing time of just under 6 hours.

We propose to observe a sample of nine very red protostars serendipitously identified in PACS observations for the Herschel Orion Protostar Survey (HOPS). In contrast to the known Orion protostars targeted in HOPS, the new sources are undetected or very faint in Spitzer 24 micron imaging of Orion. They are redder than the known Orion Class 0 protostars, and appear similar to the most extreme Class 0 objects known. These objects are likely to be in a very early and short lived stage of protostellar evolution.

With this sample, we aim to determine if the youngest protostars begin their lives in a violent energetic phase or in a more quiescent manner, slowly building their accretion and outflow power. To do this, we propose PACS Range Spectroscopy between 70 and 200 microns, observing the CO and H2O lines, and line spectroscopy centered on the 63 micron [OI] line. These far-IR cooling lines are powerful diagnostics of shock heating by outflows and radiant UV heating from accretion luminosity. Through a comparison with existing HOPS observations, these observations will be a unique window on the early evolution of outflows and accretion in protostars.

The observations proposed here are designed to search for the effect of differential heating on asymmetric dust-grains aligned with respect to an interstellar magnetic-field and heated by a localized radiation source. The grains are known to be asymmetric and aligned from observations of background starlight polarization. Modern theories on grain alignment suggest that photons from stars embedded in the foreground cloud are a key ingredient of the physical mechanism responsible for alignment. This theory predicts a relation between the grain-alignment efficiency and the angle between the magnetic field and the direction to the aligning radiation-source. This effect has been tentatively observed in a source with a very simple geometry: the aligning photons are primarily from a single localized source (i.e., a singe star) and the local magnetic-field direction is known to be fairly uniform. Such a region also has consequences for the distribution of grain heating. For example, asymmetric grains whose largest cross-sections are normal to the incident stellar radiation will reach warmer equilibrium temperatures compared to grains whose largest cross-section is parallel to that direction. This should be observed as an azimuthal dependence of the dust color-temperature. As we show in this proposal, such a dependence is hinted at in work using IRAS data at 60 and 100 micron. If this effect is real then a stronger signal is expected using longer wavelength data. Here we propose to search for this signal using Herschel/PACS photometry at 100 and 160 micron.

V838 Mon is one of the most enigmatic objects observed in stellar astrophysics in recent decades. It came to attention when it underwent a powerful eruptive outburst in Jan. 2002, increasing in luminosity by a factor of 100 over a period of 3 months. Immediately following this event a spectacular light echo was formed from the outburst light reflecting off the surrounding dust. The theories that best explain the outburst are a giant star engulfing a planetary system or a merger between a very low mass star and a very young, maybe pre-main sequence low-intermediate mass star. We obtained PACS and SPIRE (and will obtain HIFI) data of the star and the surrounding dust from a GT1 proposal. From the PACS and SPIRE maps we can see that the extended emission varies with wavelegth, and hence in dust condtions. In addition, by comparing to previous Spitzer images, we can see that the morphology of the extended emission (ISM dust) and the flux of the unresolved source (new dust forming around the star) have changed between 2004, 2007 and 2011. Hence, in this proposal we are asking for 2 additional epochs of imaging, to follow the evolution of all of this dust.

By using new laboratory transition frequencies of the H$_2$F$^+$ ion, we propose a search for the ion in interstellar space. The detection will contribute to understanding the fluorine chemistry through determined abundances of fluorine bearing molecules.

The precursor of H2F+, the HF molecule detected in diffuse molecular cloud towards W49N has a fairly large abundance of $(5.5-6.9) \times 10^{13}$cm$^{-2}$ Since the dipole moment of H$_2$F$^+$ 2.79 D is large compared with 1.89 D of H$_2$Cl$^+$, the H$_2$F$^+$ ion may be detectable in such diffuse molecular clouds where H$_3^+$ is abundant.

By considering various things, we propose searches for H$_2$F$^+$ toward three types of sources, (1) G10.6-0.4(W31C), where HF has been detected, (2) NGC 6334I, where H$_2$Cl$^+$ has been detected, (3) galactic central region sources : GC IRS 21 and 2Mass J1747, where H$_3^+$ is known to be abundant. For NGC 6334I and galactic sources, HF observations are also proposed, because of no reports for HF.

One of the key mission objectives of Herschel is to understand the role of water vapor in various environments, including in protoplanetary disks. Water has an immediate relevance to the formation of planets and to our own origin. We propose to obtain deep PACS/SPIRE line spectra of water, OH and CO in protoplanetary disks selected to have strong rotational water vapor emission at mid-infrared (10-36 micron) wavelengths (the newly discovered mid-infrared molecular forest). The mid-infrared lines trace warm to hot gas formed within a few AU from the central star. The proposed observations will relate the oxygen chemistry and transport of water in the inner few AU with that of the cooler outer disk - 1-100 AU - as traced by the PACS water lines. The Spitzer observations suggest that water vapor may be strongly depleted in the disk surface beyond 1 AU although gas and dust temperatures are high enough to maintain abundant water in the surface out to at least 10 AU. It is not understood whether this is due to chemical effects, radiative transfer effects or whether the water vapor can diffuse downwards to colder layers where is can freeze out and settle to the midplane. Measuring the radial abundance structure of the water emission by combining Herschel and Spitzer spectroscopy of water vapor is a critical step to distinguish between these scenarios and to constrain detailed disk models. Based on model fits to the mid-infrared lines, we predict very strong differences in the 50-200 micron water lines, depending on the distribution of water in the outer disk surface. We requested time to observe 8 disks in OT-1, but were awarded time for 4. This is a proposal for time to observe the remaining 4 in order to gain statistical confidence across a range of disk accretion rates and to probe the influence of disk winds on the properties of the distribution of water vapor.

Debris disks are the signposts of planetary systems: collisions among asteroidal and cometary parent bodies maintain the observed dust population against losses to radiation pressure and P-R drag. While hundreds of debris disks are known from far-IR excecss emission around main sequence stars, the best- understood systems are the ~20 that are spatially resolved. Disk images establish the size scale of an exoplanetary system. They can reveal central holes, rings, gaps, warps, and asymmetries in the dust distribution which indicate the presence of planetary perturbers. Disk images at different wavelengths are sensitive to dust grains of different sizes, and thus provide a way to trace dust transport and segregation processes.

In spring 2011 we discovered large new debris disk in HST coronagraphic images. The new system is an eccentric ring with a sharp inner edge and cleared central zone, and thus is remarkably similar to the classic Fomalhaut debris ring. Spitzer only detected the system at a single wavelength. We propose PACS and SPIRE imaging photometry to fully establish the spatial and spectral properties of this new debris system, and of three other HST-detected debris disks that lack Herschel measurements. Simultaneous modeling of the far-IR images, SEDs, and HST images of these disk will provide important constraints on the physical properties and dynamical state of their constituent dust. Our small program will complete Herschel's legacy dataset for the key subsample of bright disks that are detected in scacttered light,

Our knowledge of planetary systems outside of ours is confined almost entirely to cases where the planets are close to the star. A critical stage in the development of the Solar System was the stabilization of the orbits of Jupiter and Saturn far from the Sun. What are the characteristics of other planetary systems at large radii? Planetary debris disks provide our best tool to answer this question. However, our interpretation of these systems is currently crippled by the lack, in most cases, of more information beyond a few photometric points on a spectral energy distribution. Such data can be fitted by a broad variety of quite different disk models. Resolved Herschel images of disks can provide much better constraints on models and can lead to sufficient understanding of the general behavior to help interpret even those systems where resolved images are not possible.

We have identified 17 bright disks that show marginally resolved structures in Spitzer data, suggesting a radial size of cold planetesimal belt 3 to 10 times larger than our own Kuiper Belt. Since the disk mass is proportional to the disk diameter and covering factor of the dust, these systems are likely to be associated with the most massive planetary systems, making them the possible sites where the richest, most massive and extended families of planets will form. We propose to image these disks that can be resolved well at PACS 70 micron but not in any existing Herschel programs. We will use the resolved images as well as the photometric data obtained with SPIRE to probe: (1) the properties of cold planetesimal belts as signposts of ice giants at large orbits, and (2) the diversity of outermost planetesimal zones around other stars and the underlying causes.

Understanding the composition and physical conditions of gas in the Galaxy is crucial for understanding its structure and evolution. A great deal of information is available concerning the distribution of atomic and molecular gas but traditional tracers such as CO and HI are not able to trace regions where the gas is dense enough for H2 to exist, but where any CO and other molecules are photodissociated. These regions have been called `dark gas' (Grenier et al. 2005) and have been shown to make up ~ 30% of the molecular gas in our Galaxy. If we rely on CO, therefore, we will miss a large, important component of the molecular gas budget of the Galaxy. Our goal is to use the CII emission to trace and characterize the dark gas layer in the Perseus molecular cloud complex. Here we propose an observing program to make sparse maps of the CII emission along several cuts through Perseus allowing us to trace the transition from C+ to CI. We also propose to make maps of the CI emission over the CI to CO transition zone. We will combine the Herschel observations with already existing CO and extinction maps to determine the physical conditions in the dark gas and hence to better understand the transition from diffuse to molecular gas at the edges of molecular clouds.

Galactic abundances trace the processing of primordial elements by stars from the birth of the Milky Way to the present day. HII regions, because of their short lifetimes, are ideal targets for abundance determinations because they sample the current state of the interstellar medium. We propose to observe the [OIII], [NIII], and [NII] lines of 31 well-studied Galactic HII regions with the PACS spectrometer to derive the oxygen and nitrogen abundances. We hope to address two long-standing problems in Galactic abundance measurements: 1) abundances traced in the far-infrared show discrepancies with those in the optical, and 2) HII region electron temperatures derived from radio observations, which can be used as a proxy for metallicity, are not well calibrated with abundance measurements.

We propose to map the isolated star forming region NGC 602 to characterize the temperature and density structure of the entire system. NGC 602 lies in the periphery of the Small Magellanic Cloud and is the ideal target for a complete study of a star forming region. It is distat enough (at 60 kpc) that we can map the entire region in a short time but near enough that the stellar population and the structure of the interstellar medium (ISM) are resolved. Its isolation, in the outskirts of the galaxy, means that there is virtually no line-of-site confusion, and the interstellar radiation field arises entirely from cluster stars. We have already fully characterized the stellar and protostellar content using data from the Hubble and Spitzer Space Telescopes. Now we will explore how the massive main sequence stars are driving current star formation via their influence on the surrounding ISM. We will map the photodissociation region (PDR) in the dominant [OI] 63 micron and [CII] 158 micron fine-structure cooling lines with the PACS spectrometer and in high-resolution 70 micron PACS photometry. They will allow us to probe the temperature and density structure of the PDR. We will combine these new data with our Spitzer SAGE-SMC (IRAC 3.6-8.0 micron, MIPS 24 micron) and Herschel HERITAGE (PACS 100 and 160 micron, SPIRE 250, 350, and 500 micron) broad-band imaging as well as HST optical data to integrate a picture of massive stars, star formation, and their connection with the interstellar medium on the scale of a well-defined OB association.

We propose HERSCHEL observations of molecular and atomic transitions to study the heating and cooling balance in the surroundings of young massive stars. The high spectral and spatial resolution of the HERSCHEL space telescope gives an unique opportunity to observe the most relevant cooling and heating transition lines at wavelengths which are non observable from ground-based telescopes. The objective of our proposal is to understand the role of cooling during the early stages of massive star formation. Is cooling dissipating enough energy and allowing high accretion rates in young massive stars? Where is the cooling mainly taking place in massive protostars? Addressing these questions will help us to disentangle between different theories of high-mass star formation.

One of the biggest results that have come from Herschel HIFI is the detection of cold water vapor where it would otherwise be frozen onto grains (Hogerheijde et al. 2011, Bergin et al. 2010). Surprisingly, one unexpected inference of these observations is the requirement that the photo-desorption of water be reduced by nearly an order of magnitude to reproduce the emission line observations. The interpretation of these results was the existence of a population of `dry' (reduced water-ice-coated) grains on the surface of the disk. Emission line data, however, is intrinsically model dependent with many uncertainties, even in the collisional rates. We propose here a test of the models used to reproduce the Herschel observed water emission using an absorption line study of the main photo-desorption products of water, namely gas-phase H2O and OH. This type of study is intrinsically more sensitive as it is a direct measure of the column, without the need to assume anything about the excitation conditions. Both H2O and OH are expected to be predominantly in the ground state, and therefore such a study is the only direct test of the bulk-water-vapor reservoir. This program is designed to optimize the opportunity to find water and OH in a T Tauri disk both with the ideal inclination and continuum. These results will robustly test theories of water formation in disk systems, namely the presence of a cold, UV-photodesorbed layer of water vapor sitting on the disk surface as inferred by Herschel emission measurements of T Tauris.

C+ is expected to be the dominant ion tracing the ultraviolet (UV) radiation exposed layers of young T Tauri disks. However, observational evidence of its existence has thus far eluded us. Current Herschel Key Programs using PACS include the detection of C+ as a key program facet; however, these studies have faced substantial difficulties (galactic background, strong continuum/narrow line width) in their ability to detect this intrinsically weak line. We have designed an optimized Herschel HIFI program to finally detect this line in a sample of disk systems which span a range of dust settling, and thus a range of gas mass exposed to UV radiation. This will provide a Herschel legacy product to test models of UV radiation transport and the resulting chemistry. This lies at the heart of the detailed models of disk chemistry. Therefore, this information will be crucial as we enter the era of ALMA, where resolved observations will require sophisticated modeling to interpret.

During the earliest embedded stages of star formation the young star interacts with its surroundings through high velocity shocks and UV radiation, providing feedback on the medium from which the star is forming. At the same time, in-falling gas is heated to several 100 K by the accretion luminosity. How much energy is lost from the system through each of these processes? Is there an evolutionary trend in terms of the relative contributions from shocks and UV radiation? To address these questions and to observationally differentiate the different heating mechanisms, velocity-resolved observations are required.

Herschel-PACS has revealed that highly excited CO emission (up to J=44-43; Eup ~ 5400 K) is present towards most low-mass protostars, revealing a warm/hot component not detected previously with ISO. The PACS observations reveal directly that CO is one of the best tracers of energetic processes in protostars. To quantify emission, a model was constructed incorporating the shock- and UV-heating mechanisms. While the model is successful in reproducing observations from three sources, it also makes very specific predictions regarding the line-shape of velocity-resolved high-J CO emission. The model furthermore predicts an evolutionary sequence where CO emission in younger sources is dominated by shock heating, as opposed to UV-heating being dominant at later evolutionary stages.

To test the model and its validity for more than three sources, we propose to observe the highest excited CO line possible with HIFI, the CO 16-15 line. Velocity-resolved data will immediately allow us to quantify how much emission is caused by the different heating mechanisms. Furthermore, such data will allow us to measure the different heating contributions for this line directly, thus benchmarking our model and its underlying assumptions.

At the earliest stages of low-mass star formation, observations show that mass accretion is associated with mass ejection in the form of collimated jets and bipolar outflows. The ejection activity can be traced as shocked regions, where shock waves originating from the central young stellar object (YSO) impact, and process the ambient interstellar medium (ISM) from which the star forms. This interaction generates molecular emission that is typical of the physical (temperature, density) and chemical (abundances) structure of the gas. Studying this molecular emission is the best way to understand the physical and chemical processes operating in shock regions.

We propose to follow the water chemistry through one of the most spectacular and best-studied outflows in the Southern sky, BHR71. Because the water abundance is very susceptible to energetic input (both through direct formation in the gas-phase and through release from ice-coated dust grains), it is one of the best shock tracers. To trace the water chemistry accurately, velocity-resolved observations are required to disentangle different excitation regimes.

Early Herschel results show that water excitation conditions resemble those of rotationally excited H2, i.e., high densities and temperatures of 300-1000 K. Currently, it is not possible to velocity-resolve rotational H2 lines. Herschel-HIFI has revealed that the water line profiles observed to date are very complex, and they look nothing like the spectra of other molecular traces. Water is therefore a unique tracer of the bulk of the shocked gas where the temperature is 300-1000 K.

Given the importance of BHR71 as the most chemically rich outflow in the southern sky, that makes it a key benchmark for outflow and shock modelling with ALMA, we propose to map this outflow in a few key H2O lines with HIFI. The maps will provide legacy-value information on water and shock excitation as a function of position and velocity throughout the outflow.

Understanding massive star formation is a critical piece of the star formation puzzle, yet we still do not have an unambiguous evolutionary sequence for massive stars and their environments. Herschel is the key to establishing such a critical evolutionary sequence. Probing the evolutionary sequence of massive star forming regions requires an unbiased sample of massive protostars with comparable spatial resolution. We have the largest, most complete spectroscopic sample of massive protostars: 277 sources greater than 8 solar masses observed with Spitzer in the Large Magellanic Cloud (LMC). In this proposal, we request PACS full spectral scans of 25 massive protostars (the smallest statistically varied subsample) from our survey. These 25 sources are an excellent massive protostellar laboratory as they likely span evolutionary states (from deeply embedded to revealed), are all at a common distance, are located uniformly in the LMC, have protostellar properties as derived from SED fits to the emission (giving masses, envelope properties, etc.), and exhibit other emission mechanisms (molecular gas, free-free emission, masers, etc.). We selected the 25 of our brightest sources (>20 solar masses) that dominate the emission of its clump.

In the process of establishing an evolutionary sequence for massive star formation and its environment, Herschel will provide valuable information of the protostellar regions (detections of heated envelopes, location of shocks, PDRs, etc.), and with our sample, we can observe how the spectra change throughout different evolutionary stages. Utilizing a similar approach to our Spitzer data, we will quantify spectral features through SED and radiative line transfer fitting, as well as the powerful technique of principle component analysis, which can only be accurately achieved with full spectral scans that will reap ancillary benefit for years to come.

We propose to investigate the physical, chemical and dynamical properties of a sample of newly found high-mass pre- and proto-stellar cores identified by the ``Herschel infrared GALactic Plane Survey'' (Hi-GAL; Molinari et al. 2010). We will perform observations of the o-NH3(1_0-0_0) line (and, simultaneously, also of the o-H2O(1_10-1_01) transition) that will allow us to identify both similarities and differences between the physical and chemical conditions before and after the formation of a warm/hot source inside the dusty core identified in the SPIRE/PACS maps. Hence, these observations will improve our knowledge of the earliest phases in the evolution of high-mass stars. We will also attempt the detection of the NH(1-0) line towards a smaller sample of sources, in order to improve our knowledge of the N-chemistry during early high-mass star formation.

In the early protostellar stages, fast jets powered by the nascent star, possibly surrounded by a wider angle wind, are seen to interact with the parental medium through molecular bowshocks, producing a slower moving molecular outflow cavity. The nature of the shock accelerating the outflow plays an important role in the dynamical and chemical evolution of the entrained gas.

We propose to study with Herschel the physics of protostellar outflow shocks from the observation of CO and OI lines with HIFI and PACS, in a broad sample of outflows.

These observations will permit to bring strong constraints to shock models over a wide range of parameters, and will facilitate the interpretation of current observational programs on protostellar shock chemistry and dynamics.

M15 (NGC 7078) is, quite possibly, the most unusual Galactic globular cluster. It is among the most metal-poor clusters ([Fe/H] = -2.4), yet has an extremely dusty environment. M15 is home to a dusty planetary nebula (PN), one of only four in a globular cluster, and is the only globular cluster with a dusty intercluster medium (ICM). Dust is expected to collect in globular clusters when mass-losing evolved stars eject material towards the end of their lives, but it is unclear why only M15 has been able to retain this ICM. It is possible that the dust originates in the Milky Way, as either swept-up or chance superimposed material. We propose to (1) image M15 with PACS and SPIRE to determine the ICM (and PN) dust temperature and mass, and (2) obtain PACS line spectroscopy of [C II] at 158 microns to determine whether the ICM is of Milky Way origin. These observations allow us to probe the nature of the ICM material, determine how long it has been collecting (or how quickly it is being removed), and rule out whether the material is instead from the Milky Way. The results will have broad implications for the presence of ICM in other globular clusters; if the ICM is found to be of Galactic origin, it will significantly weaken the case for ICM to be present in any globular cluster.

This proposal aims to determine the physical structure and evolutionary status of the relatively little-studied young protostar Chamaeleon MMS1. The central source has an unusually low luminosity and is embedded in an extremely chemically-rich parent cloud. It has been put forward as an example of a first hydrostatic core, but there is some disagreement in the literature as to whether or not it drives an outflow, and it may be undergoing episodic mass-accretion. Our proposed HIFI and PACS observations of CO and H2O rotational emission lines with a range of upper-state energies will probe the density and temperature structure of the envelope and, through radiative transfer/excitation analysis, will provide crucial information on the physical state of this object. Line profiles will be used as a probe of the envelope and outflow kinematics. OI 63 micron line mapping will provide information on the envelope energetics and will test for the presence of a hidden jet. SED measurements will help to characterise the central radiation source, disk and envelope. These combined observations are expected to improve our understanding of the earliest stages of protostar evolution.

The identification of the key molecules in the interstellar chlorine chemistry has required nearly three decades. Herschel-HIFI observations have revealed H2Cl+ in absorption in various Galactic lines of sight, with abundances at least ten times higher than predicted.

Recently, the proponents have tentatively identified strong absorption signatures, observed with HIFI towards two sources, with the ground-state rotational transition 2P_3/2, J=5/2-3/2 of H35Cl+, an ion that has long been predicted to be a key intermediate, together with H2Cl+, in the chlorine chemistry of diffuse clouds.

The detection, corroborated by a good agreement between observations and models of expected opacity profiles, shows, like H2Cl+, abundances in excess with respect to the expectations.

All these findings stress the need for a revision of the chlorine chemistry and of the physical parameters at play in the environments where these molecules are found. The detection of HCl+ in other sources, especially if in combination with available observations of H2Cl+, would constitute a formidable constraint for the models. The planned observations would then have an impact, not only on the chemistry, but also on our knowledge of the Interstellar Radiation Field, of the dust opacity profile and on atomic physics parameters.

We propose to observe this HCl+ transition with HIFI towards strong continuum sources for which several molecular tracers are already available, allowing us to clarify the environment where this ion is found.

The need for Herschel is extremely compelling, since the proposed transition, the only one reasonably detectable in the ISM for this species, is in a frequency range where a strong atmospheric O3 line would complicate any attempt of observation even for the Stratospheric Observatory SOFIA. This will thus be the last opportunity, perhaps in one decade or more, to observe this molecule that plays a fundamental role in the chlorine chemistry.

We ask for a joint effort of the three Herschel instruments to carry out an exhaustive spectroscopic study of the proto−stellar jet and of the molecular outflow driven by the source IRS20 (IRAS08479−4306), an intermediate-mass star precursor, in the Vela Molecular Ridge.

IRS20 constitutes a privileged target for being, at the same time, ordinary and peculiar. Ordinary because it is the most massive object at the center of a relatively small, young embedded cluster, within a cloud located on the Galactic Plane hosting Low− to Intermediate−Mass, likely quiescent, protostars. It is thus representative of the most common Intermediate−Mass star forming mode. Peculiar because the relatively short distance, the powerful, well resolved jet and outflow, the clear edge−on geometry of its disk, and the location outside the solar circle make it very easy to study.

Exploiting the spectroscopic capabilities of Herschel and the favorable displacement of the target configuration, these observations will allow a ful characterization of morphology and physical conditions of the jet and the outflow: we plan to obtain with PACS and SPIRE a wide line survey of the source surroundings, including several molecular (CO, 13CO, H2O) and atomic (OI, CII, NII) transitions, precious for deriving the physical conditions of the source vicinity, of the primary jet and of the outflowing gas; HIFI observations of the fundamental transition of the p−H2O line at higher spectral resolution are intended to resolve features that will guide in the interpretation of the lines not resolved by the other instruments. Combining these observations with data already available, from infrared to sub−mm, it will be possible to derive for the first time the mass ejection/mass accretion rate in an intermediate−mass star precursor.

The knowledge of the properties of this class of objects constitutes a crucial junction point for better understanding the modalities of the high−mass star formation.

Herschel observations have revaled the diagnostic capabilities of hydrides, either ionized or neutral, easily detected in absorption against intense submillimeter sources. In this project, we propose to probe the diffuse molecular gas in the Galactic Center in the CH+ and CH ground state transitions. Pioneering work by Oka and collaborators have shown the existence of warm and diffuse gas (T~300K, n ~ 50 cm-3), uniquely probed by the H3+ infrared absorption lines. CH+ absorption observed by Herschel closely mimic the H3^+ line profiles towards nearby targets. As the number of stars available for IR spectroscopy is very limited, the spatial extend and dynamics of this new component is not known. We therefore propose to use CH+ as a complementary probe of this new component, using strong submillimeter sources as background targets for absorption. The CH+ observations will be complemented by CH spectra, as CH is a known tracer of diffuse molecular gas, and by 13CH+ spectra at selected positions.

We propose to perform a deep search for the CH2D+ ion with Herschel/HIFI. This species plays a key role in interstellar chemistry, especially for deuterium fractionation at moderate temperature, but also as tracer of the symmetrical species CH3+. Because of its low dipole moment, and floppy character, its rotational transitions were not accurately known until recently (Amano 2010). Also, only two millimeter transition and one submillimeter transition are available from the ground, but in spectral regions where multiple emission lines from other species are present. Therefore, this ion escaped detection despite extensive searches by some of the proponents for over 30 years. Three of the most intense lines of CH2D+ are accessible to Herschel/HIFI in relatively clean spectral regions. The detection of CH2D+ seems therefore to be finally within reach, providing a key proof of the validity of state of the art chemical networks.

Protoplanetary gas and dust disks around T Tauri stars are the most important elements in the process of planet formation. In particular, the dissipation time scale of disks sets a critical time limit for planet formation. The mechanisms of disk dissipation are poorly understood, however. Apart from the planet formation process itself, photoevaporation and disk instabilities induced by the magneto- rotational instability are key candidates. In both cases, heating and ionisation by stellar short-wavelength radiation plays a crucial role. High-energy stellar radiation (X-rays, extreme ultraviolet) also drives chemical networks in circumstellar disks, forming key molecules that eventually become important for the formation of life in habitable zones. However, there is little information on the X-ray radiation spectrum impinging on the disk, given various sources of photoelectric absorption. We will study disk ionisation and X-ray driven chemistry by observing X-ray sensitive lines in an outstanding and unique sample of three classical T Tauri stars in which X-rays appear to be blocked before reaching the disk. We will compare the results with a control sample of disks that appear to be irradiated by high levels of stellar X-ray radiation. Our X-ray sensitive lines include transitions from HCN, HCO+, and ortho-NH3. The interpretation of our results will be based on thermo-chemical codes developed in the proposing team.

Using the HIFI spectrometer on the Herschel Space Observatory we have detected the ground state lines of cold water vapor in the outer reaches of the disk around the nearby young star TW Hya. Only UV-induced photodesorption of water molecules off icy grains can explain the presence of water vapor in these cold regions. The lines of ortho-H2O 110-101 and para-H2O 111-000 are weaker than expected, suggesting that up to 80% of the larger, icy grains have settled out of the ultraviolet's reach toward the midplane, representing a 'hidden' reservoir of thousands of Earth Oceans. Analysis of the line strengths revealed a water ortho-to-para ratio of 0.77, much lower than found in Solar System comets (1.5-3), leading us to suggest that comets consist of ice mixtures from across the full extent of the Solar Nebula and implying long-range mixing of icy material in disks.

We have been awarded 47 hrs in Herschel OT1 to search three more gas-rich protoplanetary disks for the presence of ortho-H2O 110-101 at 557 GHz with HIFI (DM Tau, HD100546, and AA Tau). These targets represent, after TW Hya, the closest, mostly likely candidates to detect these weak lines.

For OT2 we propose an equally deep search for the para-H2O 111-000 line at 1113 GHz to these same three targets. These proposed observations form a unique legacy of Herschel and HIFI: together with our OT1 data, they will provide a complete inventory of cold water in these disks; they will allow us to investigate if low ortho-to-para ratios are common in protoplanetary disks or unique to TW Hya; and they will provide unparalleled insight into the origin of the Earth's oceans and the possibility of ocean-covered worlds elsewhere.

How have molecular clouds like Orion and Taurus evolved since giving birth to their first stars? The origin and evolution of molecular clouds, in particular in terms of supernova influence, can be studied through a systematic analysis of elemental isotopic composition variations in them. This approach to galactic archaeology is very promising, but little explored and so far limited to very few elements. Based on the isotopic yields of supernovae (SNe), and on existing observations, we propose that the 20 SNe that have exploded in the Orion A cloud in the past 10 Myr have substantially altered the chlorine isotopic composition and that this variation is detectable with HIFI.

The sensitivity of HIFI allows, for the first time, to perform a systematic study of sources in Orion and Taurus to map the chlorine isotopic ratio and to learn quantitatively about the Orion supernovae of the past 10 million years. This work will also contribute to our understanding of supernova-triggered star formation and ejecta-enrichment of protoplanetary nebulae.

Numerical simulations have suggested that giant molecular clouds (GMCs) can form from converging supersonic flows. In this scenario, the dynamics and chemistry of gas are strongly coupled and chemical processes, such as the HI-H2 and CII-CO transition, play an important role in the formation and evolution of GMCs. In particular, recent 3D magnetohydrodynamical simulations track both a detailed dynamical and chemical cloud evolution for the first time and find a significant scatter in the spatial distribution of CII and CO. This suggests that molecule formation is heavily affected by turbulence and is highly contradictory to what stationary photodissociation region (PDR) models predict. We propose to observe two boundary regions of the Perseus molecular cloud in the 158 micron fine structure line of CII using the Herschel HIFI instrument. Our proposal will test theoretical predictions from two different models (stationery vs turbulent) and address the importance of turbulence in the molecule formation. In addition, the proposed [CII] observations will allow us to explore the "CO-dark" gas in Perseus and to test the recent PDR model of the "CO-dark" gas in GMCs. The HIFI instrument will be critical to achieve our scientific goals as it provides the high enough spatial and velocity resolution to investigate the spatial distribution of CII in detail and to separate Perseus from foreground and background [CII] emission.

What is the origin of the high excitation, mid-IR water lines in protostars? Two separate shock mechanisms have been proposed: (i) an envelope-disk accretion shock at the protostellar disk surface and (ii) shocks in outflows. Past studies with Spitzer IRS data have been unable to conclusively rule out either scenario, despite extensive study in recent literature. Doing so for a sample of the earliest protostars would further our understanding of envelope-disk-protostar dynamics and perhaps inform us of the state of a protostellar disk just after formation.

From our high resolution Spitzer IRS survey of 80 protostars in nearby star forming regions, we have assembled a sample of protostars in which strong, high excitation water lines are detected. To resolve the question of the origin of water emission, we propose full PACS spatial resolution mapping in the range spectroscopy mode of one of the most luminous water emitters in our sample.

From the PACS maps we will be able to test each shock mechanism in two ways. First, we will investigate the spatial correlation between the peaks of the water emission, continuum emission, and outflow tracers such as the [OI], CO (J > 21), and OH lines. Significant spatial offset between the water emission and the continuum, and the spatial coincidence of water emission with outflow lines would rule out envelope-disk accretion shocks. Second, we will model the combined set of PACS and IRS water lines using a large grid of non-LTE models to derive the density and temperature of the water-emitting gas. High density (n>1.0E+10 cm^-3), low temperature (T ~ 200 K) solutions would favor envelope-disk accretion shocks, while low density (n< 1.0E+6 cm^-3), high temperature (T > 1000~K) solutions would favor the outflow shocks origin of water.

We propose to carry out PACS full scans of two bipolar outflows, HH~211 and Cepheus E, which have been identified from previous work as compact, well-defined, and possessing a clear pattern of emission stratification.

Recent observations from the WISH Key Program have shown that the water emission from nearby star-forming regions is characterized by high-velocity wings and spatial distributions indicative of outflow origin. Thanks to these observations, water has become a new and sensitive outflow tracer, albeit a special one compared to others like the standard low-J CO emission that has so far been used to characterize the large scale distribution of gas in outflows. According to our WISH observations, water traces a warmer component than the low-J CO transitions observed from the ground, and originates from gas that seems closely connected to the still-unobserved fast wind believed to underlie every bipolar outflow. Combining water and CO observations offers therefore a unique tool to study the different energy regimes of the gas in an outflow, and to infer the manner in which energy is transferred from the protostellar wind to the ambient gas. In order to better understand this connection between energy regimes, we propose to combine observations of a number of water lines and higher J CO transitions that lie in the PACS passband, and that recent observations have shown to be readily detectable.

We believe that our proposed observations will not only help better characterize two outstanding bipolar outflows, but will provide necessary clues to clarify the origin of water in other outflows and star-forming regions in general.

Debris disks are the remains of planetary system formation, tracing the existence of planetesimal-sized objects in orbit around main sequence stars. Current and planned surveys of debris disks (including the Herschel Key Projects DEBRIS and DUNES) are deep surveys aimed at characterising the typical population of disks and targeted at samples of a few hundred nearby objects. These deep narrow surveys are relatively insensitive to the rarities in the debris disk population, some of which may be luminous and/or massive disks that have undergone recent disruptive collisional events. We have recently shown that the primarily extragalactic Key Project, the Herschel-ATLAS, can be used as a wide and shallow survey of debris disks by combining its excellent optical coverage and statistical techniques more commonly employed to identify galaxies. The combination of Herschel-ATLAS, DEBRIS and DUNES thus forms a powerful nested tier of surveys that will be sensitive to disks across the spectrum from exosolar analogues to rare disks that cannot be inferred from local populations. In this proposal we seek time to image 23 candidate disks that we have discovered in the Herschel-ATLAS with PACS so that we may confirm them as true debris disks and model their SEDs to extract mass, temperature and fractional luminosity. We will confirm whether these disk candidates are in fact the most luminous disks yet detected.

We have recently obtained PACS/Photometer monitoring observations of 100 protostars in the ORION A molecular ridge as part of the program OT1_nbillot_1. We have built about 20 reliable light curves at 70 micron spanning a period of 2 months. We find that a dozen protostars exhibit measurable variability, with flux amplitude of up to 20\%, on weekly to monthly timescales. In some cases, the 160 micron light curve also shows variability with amplitude in excess of 10%. For a couple of sources, the 70 and 160 micron light curves appear to be in phase. The observed timescales are orders of magnitude shorter than the dynamical timescales of far-IR emitting material around protostars, which suggests that the mechanism responsible for the far-IR variability might originate from the inner region of the protostars. We have identified a couple of scenarios that could explain the observed far-IR variability, specifically the accretion luminosity variations originating from the inner disk that could lead to the heating of the entire envelope, and thus cause the far-IR variability. The other scenario involves a variable scale height of the disk inner edge that would cast a shadow on the outer disk and inner wall of the envelop cavity. Several of the far-IR variable protostars have already been observed with the PACS/Spectrometer as part of the HOPS program (KPOT_tmegeath_2). Some of the HOPS targets show rich spectra with multiple water and CO lines diagnostic of the activity of infalling envelopes, disks, envelope-disk accretion, and outflows. We propose a small (14.5 hours) exploratory program with the PACS/Spectrometer to monitor the physical and chemical conditions that prevail in the outer disk and envelope of a couple of far-IR variable protostars over a 2-months period.

Ammonia is a widely observed astrophysical molecule and a key tracer of dense gas in the interstellar medium. Inversion transitions of ammonia have been used for many years as a temperature and column density diagnostic toward massive star forming regions. Ground based observations furthermore, point to the presence of hot, presumably dense, gas close to embedded protostars. These same data, however, lack the density sensitivity to conclusively constrain the density of the ammonia emitting gas. Thus, whether or not ammonia is truly tracing the hottest, densest gas closest to an embedded protostar is effectively unknown. The rotation transitions of ammonia, which are unavailable from ground based observatories, have the required density sensitivity to resolve whether or not ammonia truly traces the densest regions close to newly formed massive stars. We propose here to use HIFI to observe seven rotation lines of ammonia toward three molecular hot cores each with clear evidence for hot ammonia. These observations provide the only way to know if this emission also probes dense regions close to massive stars. In sum, the proposed observations require only a modest time investment and represent science that only Herschel/HIFI can do.

T Cha, SR21 and HD135344B are transitional disks known to host potentially planetary-mass companions within their inner holes: NACO/SAM high angular resolution observations allowed us to detect and confirm an extremely red substellar companion located within the gap of the disc of T Cha. In the case of SR21 and HD135344B, detailed spectro-astrometric observations have revealed strongly in-homogenous warm CO-gas in the inner holes of the disks truncated close to the stars, which supports the presence of Jupiter-mass objects in the inner holes. This is supported by a tentative NACO/SAM detection of a companion candidate within the disk hole of SR 21. Therefore, we are witnessing in-situ formation of substellar objects within the disks of these three objects.

Since these disks lack of deep Herschel gas line observations, we propose to use the unique capabilities of Herschel to perform a detailed study of the gas content within the disks. This project will provide key constrains to understand the physics and chemistry that govern the early stages of planetary formation for years to come.

HD 37594 is a seemingly ordinary A8 V spectral type star at a distance of 43pc from the Sun. Spitzer MIPS observations, performed as part of a volume-limited survey of A type stars at the end of the Spitzer cryogenic mission, have shown this star to harbour an exceptionally massive cold debris disc (dust mass and temperature approx. 0.04 Earth masses and 54K respectively). This is potentially the most massive debris disc around an A type star within 50pc of the Sun, a sample which includes well known systems such as Vega, Fomalhaut, beta Pictoris, beta Leo and beta UMa. HD 37594 exhibits no signs of youth, and its optical and near-IR emission suggests it to be a normal main-sequence star, with slightly below solar metallicity, and no warm excess emission. Currently the only observational data for this debris disc is MIPS photometry at 24 and 70 um; longer wavelength and higher spatial resolution observations are required to gain any insight into this system beyond ascribing a characteristic dust temperature and highly uncertain dust mass.

We propose to image this exceptionally massive debris disc with Herschel's PACS and SPIRE, to allow modelling by simultaneously fitting a well-sampled spectral energy distribution (SED) from 24 to 500um and the spatial flux distribution in high S/N 70-160um images.

Most low mass stars form near OB associations and are hence subject to the harsh feedback of massive stars. Proplyds are in this situation. They are young stars, surrounded by a protoplanetary disk which is being photo-evaporated by the far-UV (FUV) photons emitted by massive stars. This photo-evaporation process determines the mass-loss and hence lifetime of these disks, which may result in severe constraints on the planet formation timescale. The photo-evaporation flow results from the formation of a photodissocaition region (PDR) at the surface of the disk, where FUV photons heat the atomic and molecular gas. The bright far-infrared cooling lines of atomic and molecular gas, observable with Herschel, are therefore the ideal tracers to understand the mechanisms at play in the PDRs at the surface of the disks. Unfortunately, proplyds have not been observed with Herschel. With this proposal, we will obtain key cooling lines -- [OI], [CII] and high J CO-- emitted by the dense and highly irradiated PDRs of three carefully selected proplyds in the Orion and Carina Nebulae. We will then analyze these observations in the frame of PDR and disk models, in order to provide a clearer picture of the photoevaporation process. For these observations we require 10.3 hours.

The CO/H2 ratio is commonly used in numerous astrophysical systems to determine the total amount of molecular hydrogen from observations of CO. However, our current knowledge of this fundamental quantity is mostly based on measurements of cold gas; for the case of hot gas we rely only on a couple of direct measurements, dating back to almost 20 years ago.

Here we propose to measure the CO/H2 ratio and its possible variations in hot gas. Our aim is to combine observations from Herschel and Spitzer tracing both molecules, in regions excited by protostelalr outflows. Current investigations show that emission from CO and H2 arises from gas at very similar excitation conditions. This fact provides strong indications that both molecules trace the same volume of gas, and therefore comparison of their column densities can directly lead to their ratio.

Some pre-main sequence stars exhibit peculiar wavelength-dependence of their mid-infrared spectral variability. This finding led to the proposal of a vertically extended obscuring structure in the inner part of the system that casts time-variable shadow on the outer disk. It is an extra component of T Tauri disks not considered in most disk models so far. In our previous optical-to-mid-infrared survey we could directly detect the thermal emission of this obscuring dust cloud. In order to initiate the physical characterization of the shadowing material, we propose a 70/160 um 4-epoch monitoring survey of eight young stars in the Chamaeleon I star forming region with Herschel. For half of this sample our earlier measurements already hint for the presence of a shadowing structure. Simultaneously with the Herschel observations we will also arrange optical-to-mid-infrared observations from the ground. We will perform a correlation analysis between the variability patterns observed at different wavelengths, in order to understand the origin of the obscuring structure. Correlation between optical and far-infrared light curves would favor an orbiting warp or long-lived dust cloud in the inner disk, while anticorrelation is interpreted as a signature of a temporary dust cloud lifted above the disk plane. In both scenarios the probable driving force behind the origin and the temporal rearrangement of this structure is time-variable accretion. Through detailed modeling of the spectral energy distributions and of the wavelength-dependence of the variability, basic physical parameters of the obscuring structure will be derived. Together with the timescale on which its structure can change, these are important entries to learn what kind of dynamical processes occur in the inner disks of low-mass pre-main sequence stars. For this project we request 7.8 h of Herschel observing time.

A shock that can be studied in detail, using a very limited amount of Herschel time, is the Herbig-Haro object HH54 located in the nearby Chamaeleon II cloud at a distance of 180 pc. The shocked region has an angular extent of roughly 30'' and is not contaminated with emission from other nearby objects. The gas, traced by H2O and CO, emits radiation predominantly in the far-infrared regime. For that reason, this program can only be executed using the instruments aboard the Herschel Space Observatory.

We propose spectroscopy of rotational H2O and CO transitions, falling in the wavelength range covered by SPIRE and PACS. These observations will allow us to stratify the shocked region in different physical/kinematical components. We will also improve our understanding of the mechanisms responsible for water production and destruction. Given the relatively large angular extent of the region, we will determine the types of shock responsible for the emission in different positions along the shocked surface. We also propose HIFI observations of selected CO and H2O transitions. A bullet feature has previously been observed in several CO line profiles. Using HIFI, we will constrain the origin and physical properties of the region responsible for this emission.

With this proposal, we aim to measure the water vapor abundance in two nearby dark clouds with different physical and chemical characteristics, following the successful recent Herschel results of Caselli et al. (2010; 2011, in prep.) toward the pre-stellar core L1544. These measurements are crucial to finally put constraints on poorly known parameters which regulate the chemistry of Oxygen: photodesorption and freeze-out/ desorption rates. Such parameters are at the base of astrochemistry and their large uncertainties affect our interpretation of observations toward molecular clouds and star forming regions. Herschel OT2 is a unique chance to observe water vapor in regions not affected by protostellar feedback and with simple structure, two necessary conditions to obtain unambiguous results.

Together with the existing Herschel data on L1544, the proposed observations will provide three detailed (legacy) studies aimed at exploring fundamental processes crucial for understanding Oxygen chemistry and for the overall interpretation of interstellar medium observations (including Herschel data).

This proposal will help answer two major open questions in the field of star formation: 1) What causes a particular region of a molecular cloud to attain high densities on the way to forming a star cluster? 2) What is the physical structure of such ``pre-star-cluster" massive clumps?

We plan to study the structure and kinematics of the envelope and the dense gas in four massive (M > 100 M_sun) pre-star-cluster clumps embedded in Infrared Dark Clouds. The selected objects have physical and chemical properties which resemble scaled-up versions of low-mass pre-stellar cores (they are cold, dense and show large abundances of deuterated molecules). They are also dark at 24&70 micron within the Herschel beam in Band 1. Therefore, they are the ideal targets where to study the initial conditions in the process of high-mass and stellar cluster formation.

We plan to simultaneosly observe ortho-H2O(1_10-1_01) (in absorption) and ortho-NH3(1_1-0_1) (in emission) to study the kinematics of the clump and the embedded dense cores. These results will also be compared to recent work toward low-mass pre-stellar cores to study how different environments affect the chemistry and the dynamical evolution of the earliest stages of star formation.

We also plan to observe CO(8-7), (9-8) and (10-9) to investigate if turbulence dissipation and shocks play an important role in the formation of dense cores and fragmentation of massive clumps. These observations are based on comprehensive MHD shock and PDR model predictions.

The 158 micron line of ionized carbon is the strongest single long-wavelength emission feature from the interstellar medium and is the most important coolant of gas in which hydrogen is in atomic form. It is a key determinant of the evolution of these largely atomic regions into denser, cooler molecular clouds in which new stars are formed, and is widely used as a tracer of star formation in the Milky Way and other galaxies. There is, however, an ongoing, serious controversy about the origin of the [CII] emission, which has been asserted to come from the extended low-density warm interstellar medium, but has more generally been associated with the primarily molecular photon dominated regions (PDRs) intimately associated with massive, young stars. We propose a combined HIFI and PACS study of the two far-infrared [NII] fine structure lines in order to resolve the important question of the fraction of CII emission that arises in ionized gas. Specifically, we will (1) utilize the fact that due to its ionization potential NII is found only in HII regions, and with PACS 122 and 205 micron observations, determine electron densities in a sample of such regions in the Galactic plane; (2) utilize available data on radio free-free and H-alpha emission to determine the NII column densities and from this the CII column densities in the HII regions; (3) use the electron densities to determine the fraction of CII emission arising in the ionized interstellar medium. These observations will be carried out at 150 of the positions in the Galactic plane observed in [CII] by the GOT-C+ project. We will also carry out HIFI observations of 10 selected positions in the 205 micron line to determine spectral characteristics of the NII emission line, which with CII, CI, and CO profiles already in hand will serve as a further discriminant among the proposed sources of CII emission.

We propose to observe the circumstellar disks around 28 very low mass stars that lie between the sub-stellar limit at 0.08 msun and 0.3-0.5 msun, the level where disks are bright enough to be readily detectable in the large, shallow Herschel surveys. The objects are located in 4 different star-forming regions that span a range of ages from roughly 1 - 3 Myr. This sample will provide the data necessary to link our understanding of disk evolution around solar-mass stars to those around sub-stellar objects, already well-represented by Herschel GT1 and OT1 programs. We will use proven disk modeling codes developed by team members and used extensively for modeling disks around stars and brown dwarfs. This approach has already worked well in our GT1 program on sub-stellar objects and in our first publication about its initial results.

We propose SPIRE photometry of the brightest 8 brown dwarfs detected at both 70 and 160um in our GT1 program that has just completed observing 50 BD's. These 8 BD's are expected to be detected at 250-350um and half are also likely detectable at 500um. The addition of longer wavelength data for even this 20% of our sample will enable much stronger limits to be placed on the geometry of the outer disks, the grain size distribution, and the total disk masses. With the ultimate goal of adding ALMA photometry and imaging at longer wavelengths, we will be able to derive much more accurate physical parameters of the disks around these objects by using the entire SED from 1um to 1mm.

Understanding the origin of the elements in the Solar system is an outstanding question of modern astrophysics, cosmochemistry, and astrobiology. The origin of nitrogen, though amongst the five to six most abundant elements in our local Universe, remains poorly understood. This is due to the lack of observational constraints to nucleosynthesis models. Elemental isotopic ratio is an extremely powerful tool in this regard. A value of 440 for the 14N/15N ratio has been measured in the protosolar nebula. Similar values have been obtained in cold dense cores and in molecular clouds. Determinations of the 14N/15N ratio in the interstellar medium (ISM) are indirect and are based on abundance ratios of N-bearing molecules and their 15N isotopologues. Hence the interpretation in term of 14N/15N depends on chemical fractionation processes. Chemical models indicate that these processes strongly affect nitriles, and recent observations suggest that ammonia is probably not a reliable tracer for the 14N/15N ratio. Nonetheless, reliable methods to determine the 14N/15N ratio in cold and dense gas seem to emerge. The same is unfortunately not true for the diffuse ISM where very little is known regarding the nitrogen isotopic ratio, which should be representative of the nucleosynthesis products. One measurement in the diffuse interstellar medium (ISM) led to the small value of 240. However, this determination is based on the nitriles HCN and HC15N, and the translation into 14N/15N is strongly model-dependent. Chemical considerations show that the NH molecule is not fractionated in the diffuse gas such that the 14NH/15NH abundance ratio is the best proxy for the 14N/15N ratio. The NH molecule has been detected by Herschel/HIFI in several diffuse clouds and offers a unique opportunity to determine the 14N/15N ratio in the diffuse ISM. The proposed observations aim at the first detection of 15NH in the ISM which will allow the first robust determination of the 14N/15N isotopic ratio in the diffuse ISM.

Massive star formation remains one of the major challenges of modern astrophysics. One key ingredient which is still poorly understood are the massive outflows which are observed near 100 % detection rate toward massive protostars. The CO molecule is in principle the best probe of the flows, however most work has been done with low-J transitions which can only probe the outer swept-up layers of the flows. High-J CO transitions on the other hand probe the warm gas very near the massive protostars and are ideal probes of the physics and role of the flows in the formation of massive stars.

We propose to obtain observations in the CO(10-9) and 13CO(10-9), C18O(10-9) and the CO(16-15) lines toward a sample of 4 massive protostars which drive massive flows. We will join these data with existing lower and mid-J CO data, EVLA continuum and SPITZER/IRAC data. We will carry out radiative transfer calculations of the CO lines to determine their physical properties as function of velocity. All data together will be used to investigate the driving and collimation mechanisms and and to develop coherent models for the massive flows.

With the discovery of G77-61 (Dahn et al. 1977) at a mere 58 pc and therefore relatively low luminosity, a category of dwarf carbon (dC) stars was finally recognized. This, however, presented a puzzle because a low mass star is incapable of the helium fusion needed to create the carbon seen in its atmosphere. A reolution was proposed and generally accepted a second member of a system could 'dump' carbon on it through an AGB stage into a circumstellar disk which would replenish the fully convective atmosphere in a reasonable period.

Current understanding of the formation and evolution of dC's is, however, limited by the small number of objects and observations. We propose observations of each carbon dwarf with Herschel PACS 100/160 um, to to detect the proposed redsidual circumstellar disk. The proposed model for creating carbon dwarfs is based on three objects and the mechanism for dumping material on these low-mass stars and building the debris systems are currently unexplored. Thus the opportunity afforded by thisr program to add observational proof is valuable, especially for the very ill-studied carbon dwarfs. Only Herscehl can provide the spectral range and sensitivity to gain the observations needed in understanding the cold circumstellar disk and dissipation timescales around evolved stars placing carbon in our ISM - a building block of life as we know it.

Ultracompact (UC) HII regions represent one of the earliest phases in massive star formation. They are characterized by extreme UV irradiation (G0>10^5 Habings), small physical scales (<0.1 pc) and are embedded in dense molecular clouds. HII regions are expected to expand at velocities of the order of the sound speed (10km/s) and remain ultracompact for about 3000 years. Therefore, only a few dozen should exist in the Galaxy. However, many more UCHIIs have been observed, corresponding to lifetimes one to two orders of magnitude larger. A number of models have been proposed to solve this problem, but all have shortcomings. Our ability to test these models depends on good informations about the morphology and the kinematics of the sources.

Mon R2 is the closest ultracompact HII region (d=830 pc), the only one that can be resolved by Herschel and undoubtedly a case study. Full modeling of the CO lines previously observed with HIFI suggests that the high velocity gas arises from the layer of warm (>100 K) and dense (>5x10^6 cm-3) gas confining the UCHII region. The line profiles are well reproduced assuming that this layer is expanding at the relatively high velocity of 1.5km/s, corresponding to a lifetime of about 10^5 years. Our kinematical study of the region is however limited by the scarce HIFI observations that hinder a full 3D modeling. We propose to observe with HIFI fully sampled maps of several atomic and molecular species (CII, CO, 13CO, CH, CH+) and single pointed observations of OH+ to trace the kinematics of the different phases of MonR2.

The understanding of the dynamics and energetics of UCHII regions is key to study the feedback process of newly formed massive stars in their native molecular cloud, and therefore the evolution of giant molecular clouds. In extragalactic research, these energetic environments could dominate the physical and chemical conditions in evolved starbursts like M82 and in the most distant galaxies.

One of the key questions dealing with the gas is how much water is present in disks and how widely is it distributed.

During the systematic data reduction of Herschel Space Observatory GASPS KP we have detected a water emission that was not expected. This line istracing warm, intermediate temperature (400 to 1000 K) water and could be the link between the Spitzer observations of hot water in disks in the mid-IR, from the inner most parts of the disk, and the observations of cold water with Herschel in the far -IR, tracing the outer regions of the disk. Our present sample of warm water detections have 10 targets with solid detections, i. e., 12% detection rate, and another 18 tentative detections, with signal-to-noise ratios between 2 and 3.

With the presental proposal we ask to spectroscopically observe the tentative detections in order to get the required sigma level for a solid detection. We ask for PACS line spectra for ten Taurus sources with tentative detections. If all the detections turn out ro be real, we will double the size of the sample and geta much larger detection rate of 28%.

Diffuse molecular clouds were long thought to constitute a mere transitional phase between fully atomic clouds and fully molecular clouds. Because of their low densities and high UV radiation fields their were expected to be relatively devoid of molecules. However, in the last three decades, a substantial number of Galactic sightlines were observed both at high UV sensitivity with FUSE and HST and at high spectral resolution in the optical that demonstrated that these clouds had a surprisingly rich and still largely unexplained chemistry. The occurrence of absorbing clouds that intercept sight lines that contain both bright UV/optical continuum sources and bright sub-mm continuum is rare. However, we uncovered three sight lines previously observed in the UV/optical that intercept foreground clouds that can also be probed in the sub-mm. We propose to use Herschel/HIFI to obtain high-resolution spectra of HF, CH and CH+ toward these 3 sight lines. The proposed observations will gives us the unique opportunity to: (1) to calibrate the HF/H2 ratio by using "measured” FUV H2 column densities and HF with those predicted by the HF chemistry; (2) to confirm that the absorbing gas clouds probed in the sub-mm have column densities similar to those observed in the UV/optical; and (3) to estimate the H2 column using the HF measurements from HIFI toward one of our target star for which direct FUV H2 measurements are not currently available. The combined UV/optical and sub-mm observations will lead to measures of the atomic and molecular abundances in the probed absorbing gas. Since the probed material are considered clouds in transition from diffuse to molecular clouds, knowing their depletions would give an insight into the processes leading to star formation.

The scenario of colliding flows driving molecular cloud formation (Vazquez-Semadeni et al. 2011; Hennebelle et al. 2008; Heitsch et al. 2008) is currently the most promising to explain the short star formation timescales and filamentary geometries observed (e.g. Hartmann et al. 2001). In this framework, molecular clouds are never in equilibrium state, as part of the cloud collapses while most of it disperses. High-density seeds result from the compression and gathering of material at stagnation points. Therefore, the structure and kinematics of these high-density clumps/cores and their surrounding low-density clouds may still reflect such a process. Especially, at the stagnation points (tips of the converging filaments), strong thermal fragmentation amplifies, shocks can emerge to shed the kinetic and thermal energy away from different gas flows (Heitsch et al. 2008). At the meeting layer between the converging flows, the reversed shocks will become an incubator for the cores to self-gravitate and collapse to form stars (Gong et al. 2011). Thus, evidences of converging flows can be found through a combined observations of velocity gradient/jumps toward the center, presence of protostars and signature of shock layers. We propose here to image water emission arising from the high-density ridges hosting the high-mass protostars W43-MM1 and MM2, which we have detected extended SiO emission, a hint to converging flows. Water emission is an ideal tracer to distinguish coherent kinematic patterns of converging-flows shock from the abrupt pattern of the outflow or hot core; to trace the velocity field of the converging flows from the outskirt to SiO knots to better constrain the pre- and post-shock conditions in W43, the connecting to the pre-converging low-density cloud; to determine the layer where shock terminate and leave only the fragmented dense cores hosting high-mass protostars.

The heterodyne instrument HIFI aboard Herschel is the only instrument that will be able to observe molecular oxygen from astronomical objects outside the solar system for decades to come. We encourage the HOTAC to endorse this proposal that aims to understand the formation and destruction of O2 in the star forming interstellar medium (ISM), including its important interplay with the energy balance and chemistry of the gas and dust. We select one of the very few regions where O2 has been detected with Herschel, i.e. the nearby (120 pc) rho Oph A cloud core. Its proximity allows high spatial resolution, where different physical regions are distinctly resolved, viz. dense prestellar cores, shocks due an outflow from a Class 0 protostar and an extended photon-dominated region (PDR). Of importance is to understand to what extent O2 sources are compact and dense or more uniformly extended. Mapping these regions in the 487 GHz O2 line with HIFI, and complementing with a higher excitation line toward the shock region, will yield convincing evidence which of these are the main contributors to the O2 emission and identify the major physical and chemical processes responsible for its abundance. This has been inferred to be lower by orders of magnitude than what had been predicted by early models. Oxygen chemistry forms the backbone of astrochemistry, and oxygen-bearing species generally dominate the cooling of molecular gas. This proposal seeks to understand the basic processes that dominate the major species involved in oxygen chemistry. With our proposed observing programme, in combination with adequate theoretical modelling, a long standing riddle will finally find its resolution - a true legacy of Herschel and HIFI!

An increasing amount of evidence, both from radio and NIR data, seems to indicate that RCW 49, one of the most luminous and massive HII regions in the Galaxy (Paladini et al. 2003), harbors Anomalous Microwave Emission (AME).

Here, we request PACS and SPIRE mapping observations of RCW49. The proposed observations will allow us to pin down the correlation of the observed microwave excess with dust emission, hence ruling out the possibility that this can be attributed to embedded UCHII regions. In addition, they will also make it possible to perform the first accurate modeling and characterization of the properties of dust in the source, thus to identify the carrier of the AME.

Finally, the Herschel observations will have a legacy value, since, by providing the first FIR images of RCW 49, they will allow the unprecedented accurate estimate of its luminosity, mass, Star Formation Rate, as well as the possible identification of triggering sites.

Using CO to trace the total H2 column density in molecular clouds is a common practice. This practice, however, can be fraught with difficulties. First of all, CO is often optically thick, especially towards the highest column density regions in molecular clouds (where stars are born) and so the analysis of CO emission requires complicated radiative transfer modelling. Second, the conversion from CO to H2 relies on an often unknown conversion factor and so a canonical value of 1:10,000 is usually assumed. This is especially problematic in cold (T < 20 K) dense gas, in which CO can be depleted onto dust grains. However, in warm gas surrounding massive or even low mass protostars (so called "hot cores''), depletion can be circumvented and the rarer isotopologues (13CO, C18O and C17O) are optically thin enough that they can be used as column density tracers.

We propose to use Herschel/HIFI to directly derive total C18O and C17O column densities in a number of high mass protostars. The method we will use offers an unprecedented opportunity to derive this fundamental quantity in a model independent fashion. The basic idea is simple. For an optically thin line the observed integrated emission is proportional to the column density in the upper state. This quantity can be derived without any assumptions regarding density or temperature. If you observe enough transitions of C18O one can simply estimate the total column from summing all the observed states and correcting for the missing population. In high mass star forming regions, the high densities and temperatures mean that the higher-J states can be significantly populated and an estimate of the total column density based on only a few low energy transitions can be seriously in error. With HIFI, we have access to > 7 high-J C18O transitions, and therefore we can calculate the total C18O column densities with great accuracy.

Embedded protostars are underluminous compared to model predictions of constant mass accretion rates from the envelope to the young star. This "luminosity problem" can be explained by episodic accretion: most of the mass is accreted in short bursts, so that most of the protostars are observed in a quiescient, low-luminosity state. The timescale between such accretion bursts is on the order of 10^4--10^5 yr. Smaller brightness variations (factors of at most a few) are seen on shorter timescales (days to years) in the more evolved T Tauri phase. Similar small-scale, short-period variations likely occur in the earlier embedded phases, but they are difficult to observe because of the high extinction through the envelope at UV to IR wavelengths. We propose a novel way of studying variable accretion in the embedded phase by obtaining a second epoch of Herschel-PACS data on rotationally excited CO lines in a sample of 21 previously observed embedded protostars. The high-J CO lines (upwards of 10-9) originate in UV- and shock-heated gas in the inner ~1000 AU of the envelope. The UV field and the shock strength are both tied strongly to the accretion rate, so variability in the high-J CO line fluxes can be used as a proxy for variability in the accretion rate. A second epoch of data on the CO 14-13, 16-15, 24-23 and 30-29 lines will reveal to what extent embedded protostars show variable mass accretion rates on timescales of up to a few years.

As matter flows from the ice-cold envelope onto a forming protostar, it heats up from temperatures of 10 K to more than 100 K. The region where the temperature exceeds 100 K (the hot core or hot corino) is where the molecular envelope connects with both the seedling circumstellar disk and the bipolar outflow. As the envelope contracts from larger scales, a lot of material passes through the hot core before accreting onto the disk. The hot core is therefore a crucial step in establishing the physical and chemical properties of planetary building blocks. However, little is yet known about hot cores. How large and how massive are they? How hot are they? Are they exposed to strong UV or X-ray fluxes? We propose the rotationally excited 3(12)-3(03) line of H2-18O at 1095.6 GHz (E_up = 249 K) as a novel probe into the properties of hot cores. This line was detected as a narrow emission feature (FWHM ~4 km/s) in a deep integration (5 hr) in the Class 0 protostar NGC1333 IRAS2A. Comparing the line intensity to radiative transfer models, we find a tentative H2-16O hot core abundance of 4x10^-6. This is a factor of 50 lower than one would expect from simple evaporation of water ice above 100 K. Why is the hot core of IRAS2A so much "drier" than expected? Is most of the water destroyed by UV photons and/or X-rays? We propose to measure the water abundance in the hot cores of a sample of five additional Class 0 and I protostars by obtaining deep integrations of the 3(12)-3(03) lines of H2-16O and H2-18O. This mini-survey will reveal whether NGC1333 IRAS2A is unique in having a "dry" hot core, or whether "dry" hot cores are a common feature of low-mass embedded protostars. If they are a common feature, it means they are a more hostile environment than previously thought, with high fluxes of destructive UV photons and X-rays.

Dust particles represent only about 1% of the mass of the Interstellar Medium but play an important role in star and planet formation. Maybe one of the most important aspects is that the process of forming planets from centimetre grains depends on the chemical composition of those grains. Chemical models, which (indirectly) take into account this composition, are hence performed to investigate the evolution from the dense prestellar core to the protoplanetary disk. However, the results of these models strongly depend on the assumed gas-phase elemental abundances. Many authors have been measuring these abundances in the diffuse interstellar medium (densities < 10 cm^-3) and have observed a gradual depletion (onto grain mantles) of gas-phase elements with the density of the clouds. However, to properly model the protostellar evolution, it is necessary to obtain a measurement of elemental depletion in clouds of much higher densities (> 10^4 cm^-3). Due to its simple chemistry, we propose to use chlorine for this purpose. We will target low-mass protostars, in which the central region shows temperatures large enough for grain mantles to be completely evaporated. Hence all the atomic Cl that was depleted onto grains returns to the gas-phase where it undergoes ion-neutral reactions to form HCl. Therefore we can use HCl as a tracer of Cl. Based on HCl observations of the low-mass protostar IRAS16293-2422, obtained as part of the Guaranteed Time Key Program CHESS, we found that observations of the (2-1) and most importantly of the (3-2) HCl transitions are crucial in addition to the (1-0) line. We therefore propose to observe these three transitions of H35Cl, as well as H37Cl (1-0) and (2-1) (for opacity determination) at no extra cost, with the HIFI instrument in a selection of five low-mass protostars in order to put additional constraints on the fraction of the cosmic Cl in volatile form, thereby improving the accuracy of chemical models and our understanding of star and planet formation.

Radio lobes and hotspots provide invaluable diagnostics of the relativistic jet power and content in active galactic nuclei. Likewise, the interstellar medium should behave like a calorimeter for microquasar jets. However, signatures of the interaction of microquasar jets with the ISM are both fainter and on comparatively larger scales than for AGN jets. We propose here far-infrared (FIR) Herschel/PACS and SPIRE wide-field imaging observations to map the surrounding environment of the microquasar and supergiant X-ray binary Cygnus X-1. This will allow us to detect the presence of filamentary structures associated with shell shock ionisation. Measuring the shell distribution, size and speed will constrain the average jet power and provide information on the fraction of the accretion power dissipated by ejection instead of radiation. These observations, by bringing a case study of shock collisions of relativistic jets with the ISM, close to a star formation region, and potentially triggering star forming processes, will strongly contribute to the Herschel legacy.

Maps of the thermal emission from dust in nearby star-forming regions have revealed an apparent similarity between the mass distributions of dense cores (CMF) and the stellar initial mass function (IMF). Deriving the mass of a core from measurements of dust emission is not straightforward, however. The primary difficulty comes from uncertainty in the dust emissivity, and in particular the slope of the dust emissivity at long wavelengths (the emissivity spectral index). Ground-based observations of the continuum emission from cores suffer from atmospheric contamination, so the best way to derive the emissivity spectral index is from space-based observations. Through our successful OT1 proposal (OT1_sschnee_1) we are mapping the spectral energy distribution (SED) of 11 cores in nearby molecular clouds using SPIRE/FTS to determine their masses accurately and constrain the emissivity spectral index of the dust emission. Now we propose to add a unique and interesting target to our sample and acquire similar data toward L1689-SMM16, a starless core newly identified to be on the brink of star formation. These observations will be supplemented with recently acquired GBT ammonia observations of the same region to break the degeneracy between temperature and the emissivity spectral index inherent in SED fits. The proposed data will enable us to derive much more accurate core masses, test the similarity between the CMF and the IMF, and search for variations of the dust properties with environmental factors such as temperature and density.

Hi-GAL2pi will complete the 5-band far-IR survey of the Galactic Plane (GP), using PACS and SPIRE in pMode to map the two Galactic longitude areas that are not covered by the Hi-GAL KP nor its OT1 extension to the outer Galaxy. These two ~60° longitude-wide slices centered toward the cardinal directions l=90° and l=270° include critical regions with uniquely favourable observing conditions found nowhere else in the Galaxy: a) the longest available panoramic view of the Persus Arm, which is the arm with the least foreground contamination from the sun's viewpoint; b) the largely unexplored inter-arm region between the Persus and Carina Arms that spans most of the l=270° slice, that alone can be observed relatively free of confusion from our vantage point. The complete census of temperature, mass, and luminosity of filaments, clumps, cores and YSOs in these two regions will provide a spatially resolved measurement of the arm/inter-arm contrast in star formation rate (SFR) and efficiency (SFE), as well as a panoramic and unconfused view of the SFR and SFE along a full spiral arm extending from the Molecular Ring to the outer co-rotation Galactocentric radius. These observables, not accessible in the GP area covered in Hi-GAL KP or OT1 programs, will uniquely enable the critical steps in our understanding of the mechanisms responsible for the assembly, formation and fragmentation of the HI superclouds and the molecular clouds on spiral arms, and thus lay the foundations for a predictive global model of star formation in the Galaxy, that may serve as a template for Extragalactic studies. The completion of the Herschel Galactic Plane survey will establish a unique legacy that will be a keystone for all future Galactic and much extragalactic research, with data products that will be mined for decades by future generations and used for research not yet envisioned, with rich potential for serendipitous discoveries. Given our demonstrated community-oriented approach, we again waive our proprietary period.

One of the closest massive star-forming regions known, and surprisingly one of the least studied, is the Onsala 2 (ON2) complex in Cygnus at d = 1.2 kpc. The ON2 region shows numerous signs of active high-mass star-formation including OH masers, compact and ultracompact HII regions, and luminous molecular outflows. A unique feature of ON2 is that it harbors the rare and remarkable Wolf-Rayet star WR 142, a strong UV source whose hypersonic wind is driving shock waves throughout the region. We propose to conduct the first comprehensive IR study of ON2 using PACS and SPIRE, supplemented by existing Spitzer IRAC/MIPS data and high resolution Chandra X-ray data. This study will build on (and complement) our X-ray study of ON2 already in progress. Our primary goal is to develop a broad picture of how star-formation is proceeding in ON2 and to identify environmental factors that may be affecting it (e.g. ionization and shocks associated with HII regions and WR 142). We will identify and classify all IR-excess YSOs, including the population of embedded sources and low-mass YSOs about which little is yet known. We will determine if filamentary structures containing YSOs are present and will use information on the spatial distribution of YSOs relative to strong ionizing sources to search for evidence of triggered star formation. Aperture photometry will provide information on the physical properties of individual YSOs and a dust temperature map of ON2. Steep temperature gradients are expected near strong ionizing HII regions, one of which is known to be a source of hard diffuse X-rays. We also propose to obtain targeted SPIRE FTS spectroscopy of the massive YSO IRAS 20198+3716 to determine properties of the gas in its vicinity.

Water is one of the most important molecules in star-forming regions because of its high abundance. However, the relative importance of its various formation and destruction routes is not well understood. OH is a key species in the H2O chemistry as it is closely linked to the H2O formation and destruction through OH + H2 <-> H2O + H. Herschel offers a unique opportunity to study the H2O reaction network, because OH cannot be observed from the ground. The first hyperfine structure resolved OH far-infrared spectrum from the high-mass star-forming region W3 IRS5 was obtained with HIFI previously. OH emission was expected to arise from the innermost parts of the protostellar envelope. The spectrum however showed a strong outflow component. From the hyperfine resolved OH we could derive physical properties of the emitting gas and the comparison with H2O constrained the chemistry: the gas-phase OH and H2O abundances are consistent with photodesorption from grain mantles in the outer envelope. In the inner envelope almost all OH is driven into H2O, consistent with high-temperature chemistry. To obtain the lacking spatial information on the OH distribution in W3 IRS5, we propose to map W3 IRS5 with HIFI. From the map we will learn how the relative contributions from the outflow and the envelope and the H2O chemistry change with position. HIFI is crucial to resolve the hyperfine structure OH, allowing us to derive the excitation temperature, column density, and optical depth. The second goal is to test predictions from theoretical calculations of the OH with H2 collision rates. A strong asymmetry, caused by an asymmetry in the collision coefficients, in the line strengths of the two OH line triplets belonging to the same rotational states is predicted by theory. We propose to observe a second OH line triplet, which is complementary to the one from the previous observation, towards the center of W3 IRS5. Comparison of the two triplets will allow us to test the predictions and to validate the rate coefficents.

NGC 281 is a remarkable laboratory for studying the complex interactions between a massive star and a molecular cloud. Chandra and Spitzer data combined with ground-based data show a partial bubble of cold molecular gas surrounding an HII region. Within the HII region, an elongated bubble of 10~MK gas is detected by Chandra. We propose PACS and SPIRE observations to map the distribution of dust and protostars in NGC 281. The distribution of protostars will be used to search for triggered star formation at the cloud/HII region interface and to examine evidence for two modes of triggered star formation. The dust distribution will be used to map the interaction of the molecular cloud and the HII region. Of additional interest is the presence of dust toward the hot, X-ray emitting gas. Such dust may facilitate charge-exchange with ions giving rise to high energy lines observed in the hot plasma.

Low mass stars form in dense cores of gas and dust. Many details of how this happens are unclear. Sensitive continuum mapping observations at wavelengths that sample the peak of their SEDs (100-300 microns) are needed, for a large ensemble of cores, in order to investigate dense core evolution. Isolated dense cores are the best place to study core evolution, as they are free of the confusing effects of star formation in large clouds and clusters. We propose to map, in the continuum with PACS and SPIRE, a large ensemble (of order 150) of isolated dense cores spanning a range of peak extinctions and star formation activity. By combining these data with Spitzer and submm continuum and molecular line observations, we will determine the physical, dynamical and chemical state of each core. These results will enable us to investigate many questions relating to how dense cores form and evolve toward star formation.

Low mass stars form in dense cores of gas and dust. Many details of how this happens are unclear. Sensitive continuum mapping observations at wavelengths that sample the peak of their SEDs (100-300 microns) are needed, for a large ensemble of cores, in order to investigate dense core evolution. Isolated dense cores are the best place to study core evolution, as they are free of the confusing effects of star formation in large clouds and clusters. We propose to map, in the continuum with PACS and SPIRE, a carefully selected group of isolated cores with low peak column density (about 30 cores), to study the earliest stages of core evolution. By combining these data with Spitzer and submm continuum and molecular line observations, we will determine the physical, dynamical and chemical state of each core. These results will enable us to investigate many questions relating to how dense cores form and evolve toward star formation.

DR21(OH) is the most massive protocluster within 3 kpc and therefore serves as a perfect laboratory to study the onset of high-mass star-formation. Recent high-angular resolution observations identified flows of cold dense gas from parsec to sub-parsec scales associated with the sites of high-mass protostars similarly as it is predicted by the dynamical, fast star-formation scenario. It is however observationally challenging to find direct evidence and proof for the converging flow model. Our group has identified the most promising potential sites in the Cygnus-X complex where the shocks associated with these converging flows could be found. Here we aim for a detailed study of typical shock tracers (i.e.OI, OH and H2O lines using PACS and SPIRE spectroscopy) to reveal the signatures of the shocks as well as to study the CO ladder to constrain the excitation conditions at these sites. We also target a water line with HIFI to obtain velocity resolved spectra of the proposed shocks. This will provide a comprehensive view on these shocks and test the converging flow scenario. Herschel is the only opportunity to extensively study these molecular tracers and could provide the first direct evidence for dynamical star-formation models.

We propose sensitive PACS and SPIRE imaging photometry of four stars with important debris disks yet to be imaged with Herschel. Two of these stars (EF Cha and HD 165014) have warm debris disks *and* complex mid-IR spectral structures that provide evidence for critical terrestrial planet formation processes: the formation of large, differentiated bodies and terrestrial water delivery. Two (HD 15115 and HD 61005) have colder, extended Kuiper belt-like disks with newly discovered structures likely induced by massive jovian planets. Our PACS imaging of the first sample will help determine whether these terrestrial planet-forming systems also have Kuiper belts, features crucial to interpreting the planet-forming potential of these systems. Our PACS/SPIRE imaging of HD 15115 and HD 61005 will spatially resolve their disks to identify additional signatures of embedded planets and will constrain the disk far-IR slope and thus shed light on the collisional states of two debris disks perturbed by a planets.

We propose to observe Sgr A*, the super massive black hole in the Center of the Milky Way, with Herschel/PACS. This will yield the first detection of Sgr A* in the far infrared. This is possible despite the large background because Sgr A* is a variable source. Its emission is known in the radio to sub-mm, near infrared and in the X-rays. Sgr A* shows a steady (quiescent) emission component with small variations and in addition occasional large amplitude flares. The quiescent emission is reaches its maximum in the sub-mm. However, the extent of this bump (caused by synchrotron radiation from thermal electrons) is not clear due to missing observations in the far infrared. The proposed observations would fill that gap. The emission in flares is most prominent in the near infrared and X-rays where the variable emission is simultaneous. The far infrared can provide decisive evidence for the true link between the near-infrared and sub-mm emission: whether it is one of these two cases or some other scenario. For answering these two questions we ask for time resolved photometry of Sgr A* with Herschel/PACS.

We ask to exploit the Herschel unprecedented angular resolution and sensitivity in the critical range 70-500um, to investigate the early phases of star formation in a nearby (700pc), low- to intermediate-mass star forming region in the plane of the Galaxy, i.e. the Vela Molecular Ridge , cloud D (4.5 x 2 squared degree). We ask PACS and SPIRE in parallel mode (9.9 h) to : 1) define a robust sample of starless/protostellar cores; 2) define the census of the very young stellar population; 3) derive the Initial Mass Function and the Core Mass Function of the region up to sub-solar masses, and find the relationship between these two fundamental quantities.

Study of carbon chain molecules in the ISM is of great importance owing to the ubiquity of these molecules and their potential role as the building block of larger molecules or as products of photo-destruction of larger molecules. However the formation mechanism of even the simplest linear carbon chain molecule is still not well understood. The isotopic abundance ratio of C3/13CCC is believed to be an important probe for the chemical routes for the formation of C3, which involve C+. Using HIFI/Herschel C3 has for the first time been detected in the warm envelopes of hot star forming cores (Mookerjea et al. 2010). This has provided access to a much larger column density of C3 than was previously possible with optical and/or mid-infrared studies of C3 in diffuse clouds. The larger column density of C3 implies a higher probability of detecting its rarer isotopologue 13CCC. This detection coupled with the recent success of the Cologne spectroscopy group in identifying the 13CCC molecule in the laboratory and accurate determination of frequencies of several nu2 bending mode ro-vibrational transitions in the far-infrared has set the stage for a search for 13CCC in the interstellar space. We propose to obtain deep integrations of the brightest of the spectral lines for 13CCC towards two very strong continuum sources in both of which C3 has already been clearly seen in absorption.

Classical novae (CNe) are cataclysmic variables that undergo thermonuclear runaways every ~ 10,000 yr. During these events, they have luminosities that can exceed the Eddington luminosity for a solar mass object. This enormous luminosity drives an expanding fireball outwards at high velocity. As the dense gas clumps in this fireball cool, dust can form. About one third of all CNe form dust. Thus, it may not be surprising to find that many dusty CNe were detected by IRAS. But analysis of those detections showed that if the dust shells of those CNe had expanded freely, they would have been much too cold and faint to have been detected by IRAS given the luminosities of the post-outburst systems that are their illuminating sources. What then, is the explanation for the high IRAS detection rate of CNe? Perhaps the expanding dust shells interact with material in a pre-existing circumstellar shell surrounding these objects, and are heated through kinetic processes. Alternatively, maybe the IRAS detections were due to line emission from highly overabundant species in their gaseous ejecta. It is hard, however, to ionize this material given the observed quiescent luminosities of CNe. Since the time of IRAS, two other mechanisms have been employed to explain the mid/far-IR excesses of cataclysmic variables: circumbinary disks, and synchrotron emission. Either of these two sources appear to be more viable explanations for the IRAS detections of CNe. We propose to use Herschel PACs to obtain 70 and 160 micron photometry, and SPIRE to obtain 250, 350, and 500 micron photometry of seven dust-producing CNe spanning a wide rage of times since outburst to understand both the nature of their mid/far-IR emission, and how this emission evolves with time. Our program requires 5.9 hr.

G216 is a unique giant molecular cloud distinguished by its large mass (10^6 Msun), lack of massive star formation, sparse population of low mass stars and protostars, and cold gas temperatures. We propose PACS and SPIRE mapping of this region to map the structure of the cold dust (and gas) in the cloud and search for protostars within the cloud. With this data we will use G216 as a laboratory for studying the dependence of the rate and effiency of star formation on the density and temperature of the molecular gas. We will search for column density thresholds and Schmidt-like star formation laws previousy reported in other more active star forming clouds; with G216 we can look for thresholds and star formation laws in a unique environment provided by a massive cloud with relatively low gas column densities, low star formation rates, and low kinetic temperatures. We will also compare the properties of the protostars in G216 to those in warmer, more active clouds to assess the influence of the gas conditions on protostellar evolution

We use far-infrared rotational spectra of OH+, H2O+, and H3O+, which we collectively call hydroxyl-ions, to study diffuse gas and high ionization rate in the Central Molecular Zone of the Galactic center. Such study has been reported by using infrared spectrum of H3+, but the observable sightlines have been limited to few bright dust-embedded stars with smooth continuum. Taking advantage of the nearly continuous far-infrared dust emission near the Galactic center, we can probe the environment systematically and extensively.

It was found last year that the velocity profile of H3+ observed by ground based infrared telescope and that of H2O+ observed by the Herschel Observatory toward Sgr B are remarkably similar suggesting that they are probing similar environment. Hydroxy-ions and H3+ probes similar environment but their properties are complementary. H3+ determines temperature and density directly while the three hydroxyl-ions provide the fraction of H2 which cannot be determined from H3+, an important parameter to determine the ionization rate. They both determine the ionization rate.

27 bright targets selected from the Herschel SPIRE 250 μm image will be used as radiation source. Four of them are sightlines in which H3+ have been observed. Such observation will establish correlation between the hydroxy-ion and H3+. The rest of the 23 targets are to fill the gap and extend the region of the observation. The H3+ observations have been limited very close to the Galactic plane but we can probe high altitude using the hydroxyl-ions.

The extended observation will allow us to discuss the relation between the high ionization rate and high energy astrophysical activities such as the cosmic ray population, supernova remnants and X-ray and γ-ray emissions. The observed high temperature and ionization rate have implication on the slow star formation and top heavy initial mass function reported in the region.

We propose to make PACS spectroscopic observations of the regions on the Galactic plane, where strong [CII] emission is suggested to be present by AKARI all-sky survey observations. These regions are thought to be excited by interstellar shocks. The proposed observations will allow us to obtain a general view of the role of shocks in the interstellar medium and their effect on the dust processing.

We propose to resolve the origin of the strong [OI] 63micron and [CII] 158 micron emissions, within protostellar jet-outflow sources, detected by ISO LWS, and use it as a diagnostic of the shock conditions. Both [CII] and [OI] emission are useful diagnostics of the postshock gas, and [OI] is an efficient coolant in the high velocity dissociative shocks. Though [CII] is less important as a coolant in the shocks, its high intensities make it an ideal probe for Herschel because of HIFI’s high spatial and velocity resolution which can answer where, within a jet and wind driven environment filled with shocks and outflow cavities, such strong emissions originate. In this proposal we use the PACS and HIFI spectral line mapping of shocks in 4 representative jet/outflow sources to study their spatial and velocity structures and their association with the jets and outflows, and the entrained regions. All these jet outflow targets have strong [OI] and [CII] detections by ISO LWS and contain atomic and ionic and molecular hydrogen jets; two were selected for the presence of wide angle outflow cavities; and two were selected for their star-forming and external FUV environments. These observations will characterize the components of the [OI] and [CII] associated with the shocks and outflows and serves as templates for understanding the ISO detections in a larger sample and using them as probes in future.

We propose to use the unique viewing geometry of the Galactic spiral arm tangents , which provide an ideal environment for studying the effects of density waves on spiral structure. We propose a well-sampled map of the[C II] 1.9 THz line emission along a 15-degree longitude region across the Norma-3kpc arm tangential, which includes the edge of the Perseus Arm. The COBE-FIRAS instrument observed the strongest [C II] and [N II] emission along these spiral arm tangencies.. The Herschel Open Time Key Project Galactic Observations of Terahertz C+ (GOT C+), also detects the strongest [CII] emission near these spiral arm tangential directions in its sparsely sampled HIFI survey of [CII] in the Galactic plane survey. The [C II] 158-micron line is the strongest infrared line emitted by the ISM and is an excellent tracer and probe of both the diffuse gases in the cold neutral medium (CNM) and the warm ionized medium (WIM). Furthermore, as demonstrated in the GOTC+ results, [C II] is an efficient tracer of the “dark H2 gas” in the ISM that is not traced by CO or HI observations. Thus, taking advantage of the long path lengths through the spiral arm across the tangencies, we can use the [C II] emission to trace and characterize the diffuse atomic and ionized gas as well as the diffuse H2 molecular gas in cloud transitions from HI to H2 and C+ to C and CO, throughout the ISM. The main goal of our proposal is to use the well sampled (at arcmin scale) [C II] to study these gas components of the ISM in the spiral-arm, and inter-arm regions, to constrain models of the spiral structure and to understand the influence of spiral density waves on the Galactic gas and the dynamical interaction between the different components. The proposed HIFI observations will consist of OTF 15 degree longitude scans and one 2-degree latitude scan sampled every 40arcsec across the Norma- 3kpc – Perseus Spiral tangency.

The High Velocity Clouds (HVCs) detected in HI are an important constituent of the infalling gas fueling the Galaxy. Our understanding the HVCs is limited by the use of HI as the only velocity resolved gas tracer. One of the critical issues is the temperature and densities of these HVCs, and whether there is H2 molecular gas in them. The [C II] 158-micron line is the strongest infrared line emitted by the interstellar gas and is an excellent tracer and probe of both the diffuse gas in the cold neutral medium (CNM) and the warm ionized medium (WIM). Members of our team have used [CII] is an efficient tracer of the “dark H2 gas” in the clouds in the Galactic plane that are not traced by CO or HI. Here we propose HIFI [CII] observations of the HVCs in Complex C observed by Spitzer, and in the DRACO and UMAEAST fields, selected from the early results of diffuse interstellar dust observations by Planck. It is important to search for the hidden gas using other tracers such as [C II] because it gives us information about the transfer of mass from the halo to the disk. In addition to the C+ emission in the HVCs, our observation will characterize the WIM and the CNM clumps in a few intermediate velocity clouds (IVCs) and high latitude local HI gas with high sensitivity.

RX J1852.3-3700 is a nearby 10 Myr old 1.1 Msol T Tauri star, harbouring a well-characterized transitional disk with an inner hole in its dust disk corresponding to the Saturn/Uranus zone in our own solar system. Based on observational constraints on the CO and H2 gas mass, the disk is likely in the process of gas clearing. As part of our Herschel program to search for remnant gas in well-studied 10--150 Myr disk systems, we have recently detected [OI] 63 micron in this disk.

Based on the thermo-chemical disk models of Gorti & Hollenbach (2004), we have identified two possible disk configurations that could explain the observed [OI], are consistent with the non-detections of CO and H2, and that differ significantly in predicted radial extent, gas masses, inferred gas-to-dust ratios, which point at different scenarios for gas dispersal and prospects for planet formation.

We propose to obtain deep PACS spectroscopy of the [CII] 158 micron line, with the goal of constraining the spatial extent of the gas distribution, and thus discriminate between the two scenarios.

Understanding the mass transfer and dynamics among the Galactic Center, the disk, and the halo of the Milky Way is fundamental to the study of the evolution of galaxies and star formation. Recently several giant loops of molecular gas (GML) have been found in the Galactic Center from CO maps, which are likely the result of the magnetic Parker instability. There is new evidence of a possible connection between these loops and the Central Molecular Zone as shown in a sparse [CII] sampling made by the Herschel Key Project GOT C+. Here we propose to map various features of the GMLs and the interface region in [CII] with HIFI. We will also map the foot points of the loop, which are thought to be highly shocked regions, in the ortho 110-101 line of water, which is a known shock tracer. With this data we will characterize different ISM components and their flow among these Galactic Center features.

We propose PACS line spectroscopy observations as well as partly photometry to estimate the Si and Fe gas-phase abundance with a clear separation of the contribution from the ionized and photodissociation region (PDR) gas combined with Spitzer/IRS observations (GO2; ID200612) in 7 Galactic star-forming regions. With Spitzer/IRS observations the Si and Fe gas-phase abundance has been examined and the depletion of Si is shown to be clearly larger than that of Fe, but the attribution of the origin of [SiII] 35 micron and [FeII] 26 micron are very limited and individual gas-phase abundance has large uncertainties. In this proposal, we plan to separate two gas-phases of the ionized and PDR gas from taking the correlation of the [SiII] 35 micron and [FeII] 26 micron emission with [NII] 122 micron and [OI] 146 micron. The electron density derived from [NII] 122 micron / 205 micron and the PDR properties derived from [OI] 63 micron and 146 micron, [CII] 158 micron, and the total far-infrared flux will be used to convert the line intensity ratio into the ionic abundance ratio.

There is growing evidence that the star formation process is in fact highly dynamic, on timescales from days to centuries. The temporal variability is a new and powerful diagnostic tool to study Young Stellar Objects (YSOs). Depending on the time scale of the variability in the mid and far infrared we can learn about different physical mechanisms shaping their structure and dynamics. Here we propose to extend our near and mid infrared study of variable YSOs in the young open cluster IC 348 to the far infrared (70 and 160 micron) using Herschel/PACS. We will constrain the frequency of far infrared variability and compare the observed time dependent behavior with protostellar and disk models to understand its origin. Possible mechanisms include fluctuations in the accretion luminosity, or echoes of inner disk structural changes projected onto the infalling envelope or flared outer disk surface. Our sample in IC348 covers a large part of the evolutionary sequence of YSOs from class I sources to transitional disks. The cadence of the requested observations allow us to study variations on time scales from days to months that could be extended to several years using our Spitzer/MIPS data. This OT2 proposal is an essential complement of our GT2 program covering one visibility epoch,

Very massive stars are infrequently found in the unvierse. However, their influence is substantial in terms of ionization flux and total stellar wind luminosity in local star forming regions. They are also believed to be very important in the earliest star forming era of the universe where metallicities are low and more massive stars are prefentially formed. Evolved massive stars later become the sites of type II supernova explosions. However, our understanding of the evolution of very massive stars is relatively limited, and many evolutionary sequences are still possible. A fundamental set of properties for understanding the evolution of very massive is there historical mass-loss. This is, in effect, imprinted on their surroundings. Wolf-Rayet stars are believed to be the evolutionary end points of very massive main-sequence O stars before they become supernovae. Many are known to have ring nebulae of material, most frequently found from the detection of ionized shells. Probing these shells should provide better constraints as to the mass of materials (and evolution of these materials) lost during the heavy mass-loss phases that are believed to occur prior to the Wolf-Rayet phase of a star. But the lack of understanding of particularly cooler material in ejecta has made this task difficult. The use of higher resolution far-infrared sata from {\it Herschel} PACS and SPIRE data on large nebulae should enable the structures of cool materials to be finally determined and masses measured in such nebulae. In the proposed project, we investigate the environments of five Wolf-Rayet stars at high galactic latitude, which considerably reducing line of sight and confusion problems found in the plane of the galaxy. Most have evidence of molecular/neutral materials from prior measurements. Our intent is to measure the mass, indicate the extent of clumping and cool materials in the nebulae, plus searching for evidence of extended low-level emission structures and any evidence of multiple ejections.

Supernovae play a key role in the dust budget of galaxies producing dust from freshly synthesized elements in their ejecta and processing dust in their strong shocks both in the local and in the early Universe. Key to understanding the importance of the dust formed in supernova ejecta for this budget is to quantify the effects of the reverse shock in supernova remnants in processing ejecta dust, particularly for the dense knots where newly formed dust is best protected (shock velocity scales inversely with the square root of the density). Observations of molecules provide an ideal tool to determine the characteristics of dense knots processed by the reverse shock. We propose to measure five high J pure rotational lines of CO from a knot in the supernova remnant Cas A using PACS in spectroscopy mode. Bright ro-vibrational emission from CO molecules has been discovered in the near- and mid-IR by Spitzer, Akari, and Palomar but the low spectral resolution, Akari, 4.6 micron spectrum has insufficient resolution to determine the characteristics of the emitting gas, except that the emission originates from warm (~2000K) and dense (>5x10^5 cm^-3) gas being processed by the reverse shock. The proposed PACS spectroscopy observations are designed to accurately determine the excitation of CO and thereby the density, temperature, and mass of emitting CO in this knot. These are key to understanding the preshock conditions and shock velocity for this knot. Dense knots in the supernova ejecta are the best place for dust and molecules formed in supernova ejecta to survive processing by the reverse shock because the shock velocity is much lower than in the interclump medium and hence we expect them to play a key role in seeding the ISM with supernova-produced dust. The results of these observations will form the basis for studies of the effects of the reverse shock in dense ejecta clumps using our dust processing shock models.

We propose to measure the thermal CO lines J = 14-13 and J = 15-14 in the circumstellar envelopes (CSEs) of 2 of the brightest red supergiant (RSG) stars at far-infrared wavelengths in the Large Magellanic Cloud (LMC) - WOH G64 and IRAS 05280-6910. CO lines are useful for measuring molecular gas, which dominates stellar winds from low-temperature stars, such as RSGs. The scientific objectives are as follows: (1) What gas mass-loss rates do LMC RSG stars experience? Mass lost from RSGs consists mainly of molecular gas, so measurements of the gas mass-loss rate are crucial. (2) Of particular interest is the influence of low metallicities, so we will compare the gas-to-dust ratios of evolved stars in the LMC (half of the solar metallicity) and those in the Galaxy. (3) Finally, our measurements will help us understand whether or not RSGs play a key role in the life-cycle of matter within galaxies (e.g., as dust and gas injectors).

We propose to use the Herschel-PACS/SPIRE instruments to study the far-infrared spectral properties of a sample of bright evolved binary stars. All these stars are surrounded by a dusty circumbinary disc in a stable Keplerian orbit. Mid-infrared spectroscopic studies show that these discs are the ideal environment for strong dust processing, in the form of grain growth and crystallinisation. Detailed disc modelling shows that the discs are not only very dusty, but also that a non-negligible gas component must be present, to allow for the observed disc geometry. The spectroscopic capabilities of Herschel will allow to extend the spectroscopic information to the far-infrared, allowing the detection of previously unexplored or unexpected dust and gas features. This will provide invaluable information on the dust processing in the disc, and the relatively unstudied gas component.

We propose to use the Herschel-PACS/SPIRE instruments to study the far-infrared continuum emission of a sample of evolved stars. All these stars are proven or suspected post-AGB binaries surrounded by a long-lived circumbinary disc. Our analysis of SPITZER mid-infrared spectra of these stars showed that grain processing is very efficient in these discs, despite the very short evolutionary timescale of the post-AGB central star. Extending the spectral energy distribution (SED) to far-infrared wavelengths is an essential complement in constraining the disc characteristics. The long-wavelength flux is very sensitive to the amount of large grains, and thus the total dust mass, and grain-size distribution within the disc. The ultimate goal is to study the structure, formation and evolution of the very common discs around evolved binary stars, and constrain their impact on the evolution of the binary systems.

The very recent and unexpected detections of fullerenes (C60 and C70) and graphene (planar C24) in the H-rich circumstellar environments of transition sources evolving from the AGB to the PNe stage indicate that these complex molecules may be not so exotic and can form under conditions which are common to essentially all Solar-like stars at the end of their lives. This result has profound implications on our current understanding of the chemistry of large organic molecules because it demonstrates that formation of large fullerenes does not require a hydrogen-poor environment contrary to many theoretical and experimental expectations. Thus, fullerenes and fullerene-related species (e.g., multishell or endohedral fullerenes) might be ubiquitous in the Universe and continue to be plausible candidates to explain many astrophysical phenomena.

The simultaneous presence of fullerenes, graphene, and PAHs in H-rich circumstellar envelopes suggests that these carbon-based molecules may be formed as decomposition products of hydrogenated amorphous carbon grains (HACs). This HACs formation scenario seems to be supported by the strong correlation between the presence of fullerenes and the detection of the unidentified 30um feature, which could also be attributed to HACs. Interestingly, HACs display also a strong and broad feature around 60 um that can be detected by Herschel. We propose Herschel PACS spectroscopic observations of fullerene-containing sources evolving from the AGB to the PNe stage in order to test the HACs formation scenario. The Herschel PACS spectra will be examined for the possible presence of other fullerene-based molecules such as multishell fullerenes and will be compared with laboratory spectra of other fullerene-related molecules. The proposed observations will create a unique Herschel data set of high archival value and will be a step forward on our current understanding of the chemistry of large organic molecules as well as of the chemical processing of dust grains in space.

Using the HIFI instrument, we propose to investigate further the puzzling - but widespread – appearance of water vapour in carbon-rich stars. Following up on our discovery that water vapour is present in the warm inner envelope of the carbon rich AGB star IRC+10216, we will carry out a sensitive search for the minor isotopologues, H2-17O and H2-18O. The abundances of these species will provide a critical test of competing models for the origin of the water vapour present in the inner envelope. If the production of water vapor is initiated by the photodissociation of CO by UV radiation, as proposed by Decin et al. (2010) and Agúndez et al. (2010), then enhancements in the H2-17O/H2-16O and H2-18O/H2-16O ratios are expected; however, if non-equilibrium chemistry initiated by pulsationally-driven shock waves is responsible - an alternative mechanism proposed recently by Cherchneff (2011) - then no such enhancement will be observed.

The pre-supernova mass loss from massive stars can significantly enrich the ISM in nitrogen. We propose to use Herschel to determine the masses of newly synthesised nitrogen in three Wolf-Rayet (WR) ejecta nebulae. We will obtain PACS line scans of 4 IR fine structure lines for each nebula, covering the [NIII] 57um and [OIII] 88um lines, along with the density sensitive [NII] 122 and 205um lines. From these we can calculate the total ionized mass of Nitrogen along with the 57um to 88um flux ratio which will yield the N2+/O2+ abundance ratio, equal to the N/O ratio for a wide range of nebular conditions, provided the exciting stars have effective temperatures above a certain threshold value. To satisfy this constraint, we have chosen WR ejecta nebulae whose exciting stars have spectral types of WN7 or earlier, or WC7 or earlier.

The total nitrogen mass can be derived from the total nitrogen flux over all the PACS IFU pixels for both N2+ and N+. This will allow the first comparisons to be drawn between derived nebular masses and stellar yield predictions for massive stars.

These measurements will also allow us to quantify the N abundance enhancements for a significant sample of WR nebulae. This has not been possible before, due to (a) the high extinctions to many WR stars, which lie very close to the Galactic Plane, hindering optical spectroscopy of their nebulae; (b) the fact that optically-based nebular N/O ratios rely on line ratios of the trace ions N+ and O+, necessitating large and uncertain ionization correction factors, whereas far-IR observations sample the dominant ions, N2+ and O2+, as well as N+.

Currently, our knowledge of the chemistry occurring in the stellar atmospheres and circumstellar envelopes of AGB stars is far from being complete. A most powerful method to study the circumstellar chemistry is broadband spectral scans of individual sources. We propose here to perform a spectral scan of the high mass-loss rate carbon star IRAS15194-5115 in selected HIFI bands. Lines will be identified and radiative transfer modelling will be performed for most of the detected species to provide circumstellar abundances and isotope ratios. The results will be compared with those of similar spectral scans of other types of evolved objects, in particular IRC+10216, to address the efficiency of various chemical processes and their dependence on the evolution of the object. A comparison between isotope ratios determined for IRAS15194-5115 and IRC+10216 will be of special interest since these stars have most likely taken different evolutionary paths along the AGB. The proposed observations will improve our understanding of AGB stars and their role in the chemical evolution of galaxies.

The nature of the C-rich evolved stars with circumstellar envelopes (CSEs) with high expansion velocities (HVCs hereafter) is a mystery. The general theory of circumstellar dynamics, which explains velocity field for for CSEs of AGB, red supergiant (RSG) and yellow hypergiant (YHG) stars, fails to explain the properties of the CSEs of HVCs. Usually, very high expansion velocities only appear in very luminous stars, but the widely accepted Hot Bottom Burning processes (HBB) prevent RSGs to become C-rich. In fact, the standard theory predicts that C-rich RSG stars cannot exist. However, first results based on CO J=1-0 interferometric maps for the HVCs IRC+10401 and AFGL2233 show that the characteristics of these objects are very similar to that of the RSG/YHG stars. This supports the idea that HVCs are indeed C-rich massive evolved stars. Also, the chemistry found for these objects show a high abundance of C but also N, which agrees with this massive origin for HVCs.

We have also been granted with PdBI time to map the CO J=2-1 emission as well as low-J transitions of HCN, SiO, SiN and HCO+ among other molecules for the same sources. These observations will provide us important information about the kinematics and chemistry of the cold gas of the CSEs around these objects. However, massive evolved stars have CSEs significantly warmer those of their low-mass counterparts. Therefore studying the warm gas around HVCs is fundamental to obtain an accurate view of the nature, formation and chemistry of these objects.

We propose to use HIFI/Herschel to observe high-J transitions of 12CO and 13CO, as well as the emission of the water lines and ammonia for the HVCs AFGL2233 and IRC+10401. The 12CO and 13CO lines will help us to trace the warm gas of the CSE around these objects. The water observations will help to understand the formation of this molecule in (presumably massive) C-rich stars, while ammonia will provide important information about the abundance of nitrogen in these objects, and their nature.

One of the most spectacular phases in the evolution of intermediate mass stars takes place at the end of their lives. At the end of the AGB, the central star dashes across the HR diagram from the red giant to the blue dwarf region. At the same time, the spherically symmetric and slowly expanding circumstellar envelopes around AGB stars become planetary nebulae (PNe), displaying a large variety of shapes and structures far more complex. This transformation takes place at the very end of the AGB, and it is due to the interaction of fast and bipolar molecular winds with the fossil AGB circumstellar envelope. The origin of these post-AGB winds is still unclear, but we know that the resulting two-wind interactions are only active during a very short period of time, ~ 100 yr, but still they are able to strongly modify the kinematics of the nebulae and re-shape them. To better understand these processes we must study the warm molecular gas component of early post-AGB sources, both pre-planetary nebulae (pPNe) and young PNe. Herschel/HIFI is very well suited at this, because its spectral coverage, high velocity resolution, and superb sensitivity. For these reasons, 10 pPNe and young PNe were included in the KPGT HIFISTARS, were a large number of spectral lines are observed in a moderate number of frequency setups, but just at the central point. In many cases this is simply enough, since most post-AGB sources in HIFIStars are compact. However there are three cases in which the non spherically symmetric structures seen in the warm gas are larger than the telescope beam: OH231.8+4.2, NGC7027 and NGC6302. Therefore we propose to perform some additional points in these three sources in a selected sample of HIFISTARS frequency setups, were we have detected strong lines of CO, H2O, NH3 and OH. These observations are crucial to understand the kinematics and interactions traced by these warm gas probes, and gain insight in the intricate problem of the post-AGB dynamics.

We propose to perform PACS range spectroscopy around the 69 micron forsterite dust feature of evolved stars. With the spectral resolution and sensitivity of PACS we are able to fit the profile of the forsterite feature which is very sensitive to temperature and composition of the grain. Based on a sample, observed in earlier GT programmes, of about 15 evolved stars, including OH/IR stars, post-AGB and PNs, we find that the olivine dust is purely Mg-rich and contains no iron. We find differences between the 'outflow' sources and sources which have disks, likely indicating a different formation history. The modelling of the mid-infrared bands (observed with SWS) in combination of the 69 micron band of the heavily obscured OH/IR stars allows to study the dust distribution and search for deviations from spherical symmetry or changes in mass loss history. With the new observations of a new set of 13 stars we want to substantiate our findings. The combination of SWS and PACS spectroscopy will provide a legacy dataset for future studies of crystalline dust.

We propose to observe five AGB stars with low mass-loss rates using Herschel-PACS in spectroscopy mode between 51 and 73 micron. This wavelength range covers the high-excitation lines of CO and SiO that will allow us to determine the density and temperature of the inner wind where dust is being formed, and thus shed light on the actual physical conditions that determine the outcome of the dust formation process. The AGB stars with low mass-loss rates are particularly important in these studies since their IR dust spectra represent the first dust grains to nucleate, and moreover exhibit the largest diversity in dust condensation products. Our sample thus represents a subset of evolved stars that is indispensable to understand this condensation process, but that is at best highly underrepresented in currently approved evolved stars programs with Herschel. When combined with data from these existing programs, our observations will allow to make great progress in our understanding of the the dust condensation process in AGB stars. The small (2.4 hours) complementary program we propose here will thus greatly increase the scientific return of these programs.

The pumping mechanisms for astrophysical masers are often complex, involving infrared line opacities, collisions, and infrared line overlaps. Hence, the interpretation of the observed emission requires detailed modelling. In spite of these potential problems the masering lines can, however, give useful information on the physical conditions of the regions where the masers are produced, i.e., the innermost zones of circumstellar envelopes.

While SiO, OH, and H2O masers are a common feature of O-rich stars and were detected more than forty years ago, strong maser emission in C-rich stars has been detected only in some vibrational lines of HCN, and in some high-J lines of the ground state of SiS.

In the line survey of IRC+10216 with HIFI we have discovered several lasers involving the pair of vibrational levels 4v2/v2+v1. The strongest ones are above 1 THz and carry information of the 1-3 stellar radii zone. Several masers have been also found in some lines of the v2 bending mode between 500 and 900 GHz.

We would like to carry a systematic search for HCN masers in C-rich evolved stars by observing selected frequency ranges covering from the v1 to the 3v2 vibrational states (typically a range of 15-20 GHz) for each rotational line within the SIS receivers of HIFI (from J=6-5 up to J=13-12). The pummping mechanism can be different in each object depending on the dust opacity. High mass loss rate stars will have their 3 micron emission absorbed near the star by the large amount of dust produced in these objects. The pumping of HCN will be done mainly through the bending mode at 14 microns. However, in low mass loss rate the 3 micron photons will populate the v1, v3 and combination bands allowing a much complex pumping pattern.

This study will permit to characterize HCN laser emission in C-rich stars and their pumping mechanisms. It will also complement our recently granted high angular resolution observations of HCN with ALMA in cycle 0.

We have found during our GT line survey of IRC+10216 and the search for hydrides (OT1 proposal) that some molecular lines present a strong intensity variation with time due to the role of infrared pumping. For some lines the intensity change in six months reaches a factor 3 (CCH). We have checked that the effect is not instrumental and than it arises from physical processes ignored so far in the radiative transfer models.

We propose to observe the CCH and HNC lines within bands 1a-5b of HIFI every four months (three observing slots) to allow a detailed study of the variation of thermal molecular emission, and dust emission, in this prototype of AGB C-rich object. The settings will also provide, as a bonus, many lines of SiO, SiS, CS, HCN, CO and 13CO for which intensity variations of up to 30% have been found. In addition, a few specificc settings for HCN and CO will complete the observations. SPIRE and PACS observations will complement, with lower spectral resolution, the whole spectrum of each of these molecules and will provide a global view of the total intensity change of these lines with time. A crude estimate of the distance could be also obtained from the observed time lags between the blue and red parts of the line profiles observed with HIFI.

Supernova remnants interacting with dense moelcular clouds provide astrochemical laboratories to study heating and cooling of the dense ISM, shock chemistry, destruction and sputtering of dust, and the reformation of molecules. Water is expected to be a major coolant for shocks into dense gas, yet the number of remnants in which IR lines of hydroxyl and water are detected is very limited. We propose Herschel PACS, SPIRE and HIFI observations of three remnants with particularly high shocked gas densities, high dust and IR line luinosities, and extreme ionization environments. The scientific objectives of this proposal are: (1) to determine the abundance and excitation of oxygen-bearing molecules, and (2) to study the effects of variable ionization sources on oxygen chemistry in dense molecular gas shocked by powerful supernova remnant blast waves.

There is much controversy concerning the ionized nebula that produces the radio through FIR emission from symbiotic stars. The goal of the proposed Herschel observations is to test two popular models for this emission; whether it is produced by a wind from the red giant that is photoionized by Lyman continuum photons from the hot WD (STB) or it comes from plasma that is shock heated as the winds from the two stars collide by constraining the submm SED and measuring the free-free turnover frequency of the ionised component. These two models predict distinctly different shapes for the submm portion of the SED and different dependence of the turnover frequency on binary separation. Thus, submm photometry of a diverse sample of symbiotic stars with know binary parameters that only Herschel can perform is an ideal way to quantitatively test and discriminate between these models (as well as motivate new ones). In terms of astrophysical significance, determining the origin of the radio-through-FIR emission from symbiotic stars has implications for the nature and geometry of mass transfer in wide binaries, mass loss from accreting compact objects, the shaping of asymmetric nebulae around binary stars (including binary planetary nebulae), and the likelihood that symbiotic stars can explode as type Ia supernovae.

A subset of Asymptotic Giant Branch (AGB) stars loses mass at a very high rate. The dust effectively shields the radiation from the central star, allowing water-ice to condense onto existing silicate grains. Through the mass loss process, these stars provide a siginificant fraction to the gas and dust mass return to the interstellar medium. They are thought to be massive intermediate-stars (>5 Msun), close to the end of their AGB evolution.

Using Herschel to obtain the full spectral coverage from 50 to 670 micron with PACS and SPIRE, we will obtain spectra of gas-phase H2O lines and derive the H2O abundance by modelling these lines, thought to be the main cooling agent in O-rich AGB star. This, combine with a few selected high resolution observations of CO lines with HIFI will allow us to explore both the temperature and density structures of the circumstellar envelope (CSE). These observations will enable us to study the H2O abundance as a function of distance from the star as well as explore the superwind region close to the central star and detect any departure from spherical symmetry in the structure of the CSE. We will also get a handle on the stellar mass from 12C/13C and the wealth of the molecular emission lines in this wavelength range will be used to study the ongoing chemistry in highly obscured circumstellar envelopes of AGB stars.

One of the highlights of the first year of Herschel's science program was the discovery of warm water vapour in the envelope around the carbon-rich evolved star IRC+10216 (Decin et al. 2010, Nature). The water abundance derived for this carbon-rich AGB star is 4 orders of magnitude larger than the photospheric abundance expected under thermochemical equilibrium. This huge discrepancy had led to the suggestions of several possible origins for the water vapor. The relative strengths of the high-excitation water lines in the Herschel data indicate the presence of warm water vapor close to the star. Only two, still competing, theories are consistent with the existence of warm water vapor.

Very strikingly, water vapour was later on detected in eight other carbon-rich evolved stars, i.e. every star in a small sample surveyed with HIFI. Much to our surprise, recent PACS observations did not reveal the presence of water in one other carbon-rich target (AFGL3068). So far, this is the only carbon-rich star without water detection. Currently, it is absolutely unclear which are the key physical and chemical parameters determining if water will be formed or not.

The currently available Herschel observations show a very strong bias toward high mass-loss rate targets. Additionally, Mira-type pulsators with high pulsational amplitudes are favored over Semi-Regulars. We aim to extend the small HIFI sample with 10 new targets, carefully selected to cover all (circum)stellar properties thought to be relevant for the creation and excitation of water. We will observe 5 ortho-water lines and 1 para-water line, covering different excitation energies. That way, Herschel will provide us with high-quality data being key to unravel the physical and chemical conditions prerequisite for the formation of water in the sooty outflow of luminous carbon stars.

The IRAS source 19312+1950 is a peculiar bipolar nebula that has eluded firm characterisation since its discovery. It exhibits maser and outflow properties similar to a massive O-rich AGB star, but shows molecular species such as CH3OH and HC3N that are more typically found in molecular clouds or YSOs. The source is surrounded by remarkable NIR nebulosity and has an unusual SED. The puzzle over the true nature of this object is confounded by our Spitzer IR spectrum that shows amorphous silicates and CO2 ice, but also emission from what may be crystalline silicates. In order to understand the physical properties of the gas and dust in the vicinity of IRAS 19312+1950, we propose to perform Herschel observations of emission from CO and H2O across a broad wavelength range from sub-mm to IR. Observations of transitions from a variety of energy levels will allow us to probe different temperature and density regimes within the source, from which we will construct a picture of its physical structure through radiative transfer/excitation modelling. HIFI observations will allow us to separate the broad and narrow molecular line components and PACS IFU mapping will provide crucial spatial information on the physical structure of the source. We also propose to perform a PACS SED scan to better characterise the source SED, and measure diagnostic spectral features of the dust and gas such as the forsterite 69 micron band, the OI 63 micron line and the N II 122 and 205 micron lines. The combination of these unique observations will help solve the puzzle of the nature of this peculiar object.

We propose Herschel PACS and SPIRE imaging of a sample of 26 Classical Cepheids, to map their far-IR circumstellar emission. All targets have been previously imaged with Spitzer/IRAC and MIPS. Herschel data will allow to characterize the nature of the nebulosity for all sources, and differentiate it from "Galactic Cirrus'" background emission and local ISM clouds. This will provide an accurate and unbiased estimate of Cepheid mass loss rates, crucial for resolving the "Cepheids mass discrepancy'".

The detection of 0.4-0.7 solar masses of dust in the ejecta of SN 1987A is one of the most important results of the Herschel survey of the Magellanic Clouds (HERITAGE). It has provided astronomers with strong observational evidence that supernovae (SNe) can be major contributors to the dust in the local interstellar medium (ISM) and to the massive amounts of dust present in ultraluminous infrared (IR) galaxies in the early universe. The discovery has drawn some scepticism regarding the validity of the interpretation, i.e., that the 100 to 350 micron fluxes can indeed be attributed to continuum emission from dust. We propose PACS and SPIRE deep spectral observations to definitively determine the nature of the far-IR continuum emission and the contribution of molecular and atomic line emission to the observed broad band fluxes that we used to derive the dust mass. In addition to validating the dust model, any observed line emission will be used to determine the molecular and atomic abundances and the physical conditions in the material ejected from the SN.

We propose PACs and SPIRE spectroscopy of three core-collapse supernova remnants (SNRs) in the Large and Small Magellanic Clouds (LMC, SMC): 1E0102-7219, N132D and N49. They are chosen to have a range of ages and degrees of interaction with nearby molecular clouds. We will use the spectroscopy to 1) constrain shock models, 2) judge the line contamination of broadband fluxes used to measure dust mass, 3) determine carbon and oxygen abundances and gas masses and 4) understand the CO ladder in cases where SNe shocks interact with molecular clouds. SNRs play a fundamental role in the evolution of galaxies: their ejecta drives the chemical evolution of the interstellar medium (ISM), and the energy liberated in their explosion drives the shock waves that generate bulk motions in the ISM, accelerate cosmic rays, regulate the star formation rate, and alters the size and properties of interstellar dust. In order to understand the life cycle of dust, which is the overarching science goal of the HERITAGE key program on the LMC and SMC, we must investigate SNR shocks in both the supernova ejecta and the ISM. SNRs radiate from radio to X-ray wavelengths, but far-infrared (FIR)/submm observations are crucial both because shock heated dust is visible in these bands and because the FIR lines in many cases dominate the cooling in SNRs. For the first time, Herschel provides the necessary sensitivity and spatial resolution to map LMC and SMC SNRs in several critical cooling lines in SNR shocks: [O I] 63um, [C II] 158 um and [O III] 88 um with PACS spectroscopy, and CO rotational lines with SPIRE/FTS. The atomic fine-structure transition lines in the FIR are important shock diagnostics particularly for the lower densities (~50-500 cm^{-3}). The submm molecular lines will provide critical information on the interaction of SNRs with neighboring molecular clouds. Comparison of our results with Herschel studies of Galactic SNRs will reveal potential dependencies of SNR evolution on metallicity of the ISM.

Massive stars, their nature and evolution, play a important role at all stages of the Universe. Through their radiatively driven winds they influence on the dynamics and energetics of the interstellar medium. The winds of OB stars are the most studied case. Commonly, the mass-loss rates of luminous OB stars are inferred from several types of measurements, the strengths of UV P Cygni lines, H-alpha emission and radio and FIR continuum emission. Recent evidence indicates that currently accepted mass-loss rates may need to be revised downwards when small-scale density inhomogeneities (clumping) are taken into account. We argue that only a consistent treatment of ALL possible diagnostics, scanning different parts of the winds, and analyzed by means of ‘state of the art’ model atmospheres, will permit the determination of true mass-loss rates. To this end we have assembled a variety of multi-wavelength data, but one crucial observational set is missing: far-IR diagnostics of free-free emission, which uniquely constrain the clumping properties of the wind at intermediate heights. We propose, therefore, to use PACS photometric mode to fill this crucial gap, studying the 70 and 110 micron fluxes of a carefully selected sample of 29 O4-B8 stars. These observations will provide the missing information to derive the clumping properties of the entire outflow, to understand the wind physics, and to obtain reliable mass−loss rates.

Herschel has revealed that wind-ISM interaction regions and detached rings occur frequently around evolved stars. These interaction regions are observed to yield various shapes and sizes which can be divided in four main morphological classes. To first order the distance between the bow shock apex and the star is set by the stellar properties (mass-loss rate, wind velocity, peculiar motion) and the properties of the local ISM (density and temperature).

The primary objective of this proposal is to characterize and understand the interaction of stellar mass-loss with its immediate surroundings by studying the direct emission cold dust as it is trapped in the interaction region between the stellar wind and the ISM. Thus we can follow the fate of circumstellar dust, use the observed morphologies as tracers of the ISM and of the later stages of stellar evolution. Also we aim to elucidate effects of magnetic fields, binarity, and circumstellar chemistry on the shaping of these interaction 'bow shock' regions.

Herschel is uniquely equiped to trace the cold dust that is trapped in the studied interaction zones. These goals can be achieved best by performing a sufficiently comprehensive PACS imaging survey of nearby AGB stars.

We discovered more than 400 compact shells in the MIPSGAL 24 microns survey of the Galactic plane. About 15% of all these objects were already known as planetary nebulae, supernova remnants, Wolf-Rayet stars, and luminous blue variables. The unknown bubbles are expected to be envelopes of evolved stars that could account for the ``missing’’ massive stars in the Galaxy. Indeed, recent spectroscopic follow-ups in the near-IR and mid-IR have revealed several dust-free planetary nebulae with very hot central white dwarf and significantly increased the number of WR and LBV candidates.

Our OT1 Priority 1 proposal just provided us with a first observation in the PACS-SED B2A mode of one object, revealing only a strong [N II] 122 microns line. Without further spectral information, identification and modeling of the target are impossible. However, analysis of the PACS and SPIRE data from the HiGal survey has recently enabled us to measure much higher detection rates of the shells in the far-IR than with MIPS 70 microns. We are thus very confident that dust features and/or gas lines can be detected with the PACS and SPIRE spectrometers. Therefore, we request complementary PACS-SED B2B and SPIRE-FTS observations on our OT1 sample.

The complete far-IR/submm spectrum of each target will allow its unequivocal identification thanks to comparison with spectra of known evolved stars from the MESS key program. We will also model with much detail the different phases of the envelopes, thanks to our expertise in circumstellar envelopes, dust models and photoionization codes.

We propose to carry out a Herschel/PACS far-infrared (70 and 100 um) survey for thermal emission from cold (T < 150 K) dust in eleven observable core-collapse supernovae (CCSNe) known to have occurred within 4 Mpc over the past 20 years. The source of the large amounts of dust observed in high redshift galaxies has remained uncertain for nearly 40 years. Despite the success of theoretical models in condensing dust within supernova ejecta, only a handful of supernovae show direct observational evidence for dust condensation, and these examples all yield 2-3 orders of magnitude less dust than predicted by the models. The recent discovery of a large (1 M_sun) reservoir of newly formed, cold (20 K) dust in SN 1987A has revolutionized our outlook by serving as a reminder that a significant portion of newly formed dust likely exists at colder temperatures. Aside from SN 1987A, however, cold dust has only been observed in nearby supernova remnants (SNRs) due to the limited sensitivity and resolution of longer wavelength instruments, such as Spitzer/MIPS. We show in this proposal that, assuming a dust mass similar to that observed in SN 1987A, Herschel/PACS will be sensitive to cold dust down to 40 K and will provide meaningful upper limits in cases of non-detections. Given this is Herschel's last round of proposals, this is the only and best opportunity to perform the first search for cold dust in a sample of extragalactic SNe. In only 14.8 hours, we can obtain two color photometry to constrain the dust temperatures and masses in the eleven CCSNe.

This is a resubmitted priority 2 OT1 programme to scan [OIII] 88micron with PACS for a sample of Milky Way carbon and oxygen sequence Wolf-Rayet stars. The proposed observations, requiring 7.7hr will: (i) enable reliable oxygen abundances to be determined for WC stars for the first time, testing evolutionary predictions; (ii) refine the degree of clumping in the outer stellar winds of these stars derived from existing ISO/SWS or Spitzer/IRS datasets. The requested line spectra are unique to PACS and cannot be acquired with another instrument for these targets.

It is well-known that supernovae play a key role in creating and distributing elements throughout the universe, but less well-known is their contribution to the overall budget of dust in the ISM. Theoretical models suggest that core-collapse supernovae should produce large quantities of dust, but observational evidence for this is still debated. Even if significant quantities of dust are produced, does it survive the passage of the reverse shock to enter the ISM? Does the forward shock destroy all dust that it encounters? Near and mid-IR observations with Spitzer and AKARI have begun to answer these questions, but the long wavelength cameras of Herschel are necessary for a complete picture. We propose detailed observations of G292.0+1.8, a large Galactic supernova remnant (SNR) that has been called the "older cousin" of Cassiopeia A. One of the few known oxygen-rich remnants, G292 is a 3000 year old textbook example of a core-collapse SNR expanding into its own circumstellar medium (CSM), the wind of a red giant. It is one of the most well-studied SNRs at all wavelengths, from radio to X-rays. At 8' in diameter, it is large enough for the emission from the forward-shock CSM to be well-separated from that of the reverse-shocked ejecta, yet it is still small enough to be fully covered by Herschel in a reasonably small amount of time. We will obtain PACS and SPIRE imaging of the entire remnant. PACS observations will be sensitive to forward-shocked material, while SPIRE data will tell us whether large amounts of ejecta dust are present in the remnant. We will use the far-IR data in conjunction with X-ray and optical data to obtain a complete picture of the dynamical evolution of the remnant, and advance our understanding of the nature of dust in the universe.

Thanks to their Period-Luminosity law, Cepheids are among the most important class of stars. The recent discovery of circumstellar envelopes (CSEs) around Cepheids is an indication that many Cepheids, if not all, are surrounded by CSEs. The bright classical Cepheids RS Pup and delta Cephei are particularly interesting members of their famous class of variable stars, as they are known to be surrounded by large CSEs. Following our PACS and SPIRE imaging observations of the dusty circumstellar envelopes of these two Galactic Cepheids in OT1, we request spectroscopic observations of the same two targets to measure the physical conditions and composition of their stellar winds. Our scientific goal is to determine the physical conditions in the stellar winds, and pinpoint, in combination with other observations, the mass loss rate of these two benchmark stars. There is still today a significant discrepancy between the Cepheid masses estimated from evolutionary modeling, and pulsation modeling. The evolutionary modeling systematically predicts higher masses than the ``instantaneous", dynamical pulsating masses. This may indicate that massive stars experience significant mass loss episodes during their Cepheid phase. We aim at testing the hypothesis that pulsation driven stellar winds occur during the crossing of the instability strip, and are at the origin of this discrepancy.

G21.5-0.9 is a supernova remnants with bright pulsar wind nebulae powered by a young, active pulsar, and for which IR observations provide evidence of the interaction between the pulsar wind nebulae and the inner ejecta of the remnants. Combined with known properties of the central pulsar, and broadband images and the spectral energy distribution, information derived from spectroscopy of the interaction regions can place strong constraints on the evolution of this systems and on its progenitor star. Here we propose Herschel spectral mapping studies of G21.5-0.9 in order to obtain velocity and composition measurements of the inner ejecta in order to investigate the progenitor properties and the dynamical evolution of the system.

We propose to observe a sample of highly evolved planetary nebulae that we believe to have ongoing molecular chemistry inside dense knots that formed only a few thousand years ago inside recombining gas. The proposed Herschel observations will allow us to either prove or disprove this new, still controversial, formation scenario of the knots. If proven correct, these knots will allow us a unique opportunity to test the theory of time-dependent molecular chemistry. Two famous examples of such objects are the Helix nebula (NGC 7293) and the Ring nebula (NGC 6720). They have knots that are currently embedded in the ionized gas as the ionization front has moved outwards since the knots formed. The Helix nebula has very strong H$_2$ emission coming from the knots. A static photoionization model cannot explain this emission, but a hydrodynamic model can. This model indicates that the knots are quickly eroded by the radiation field of the central star. This poses a problem for rival theories as they assume that the knots formed much earlier, and must have survived through the entire photoionized phase of the nebula. We believe that the knots cannot survive that long in such a harsh environment and formed after the central star entered the cooling track and the nebulae started to recombine. In order to prove this we need more accurate models of the advection flows off the knots that need to be constrained by Herschel observations of the full CO emission line spectrum. To sample various stages of evolution, we have searched for evolved planetary nebulae with knots which were sufficiently bright. After removal of duplications with earlier proposals, we were left with a sample of 5 planetary nebulae, including the Helix nebula. We propose to obtain SPIRE full range spectroscopy and PACS deep line scans on individual CO lines, allowing us to observe the CO spectrum from the 4--3 line up to the 24--23 line.

In order to investigate the relative impact of water production in evolved stars on the ISM water budget and in order to understand accurately the water excitation in circumstellar environments, we suggest to extend the observations taken for the HIFISTARS Guaranteed Time Key Program (GTKP, P.I.~V.~Bujarrabal) for the AGB star W Hya and to complement the PACS/SPIRE observations taken within the framework of the MESS GTKP (P.I.~M.~Groenewegen). This will provide the most complete inventory of water vapour emission lines yet observed, providing Herschel with its very own water legacy. In addition to the observations already taken, the proposed number of 17 transitions for a total of 18.7 hours of observation time allows us to (1) significantly improving our knowledge on water excitation and (2) study the thermophysical structure (water cooling, wind acceleration and the dust-gas reciprocal influence) in the CSE of W Hya in all detail. In turn, we can pinpoint the radial water abundance profile, which provides information on the chemical processes responsible for forming water in an AGB environment, leading to a template for other unobserved or partially observed oxygen-rich AGB stars. W Hya is a low mass-loss rate oxygen-rich semi-regularly pulsating AGB star at a distance of 78 pc. It has a relatively well understood geometry, a large water abundance, and more importantly it is the evolved star with the strongest thermal water emission detected to date, as shown by the observations carried out for the HIFISTARS GTKP.

We propose to observe CO J=6-5 and 9-8 line emission from a cool AGB star, Y Gem, which, in dramatic contrast to most objects in its class, has relatively strong and variable FUV and NUV fluxes - evidence of variable accretion of matter onto an accretion disk in a binary system. We found Y Gem as a UV source serendipitously, while combing the GALEX archive as part of a project to look for hot binary companions to cool AGB stars. This object may represent the earliest phases of an AGB star with a growing accretion disk which will produce collimated jets that are widely believed to sculpt the round circumstellar envelopes of AGB stars into bipolar planetary nebulae. It may evolve into a member of the class of post-AGB objects which show no extended outflows, but only circumbinary disks. HIFI observations of high-J CO lines are needed to probe the warmest and innermost circumstellar regions where the hypothesized accretion disk resides and jet launching may occur. Furthermore, the proposed CO observations, together with our existing CO J=2-1 data, will allow us to accurately constrain the CO excitation temperature, and the optical depths of the CO lines and thus the total mass of the emitting region. The disk or torus mass will provide an important constraint on its formation process (e.g., common envelope evolution or Bondi-Hoyle wind-accretion/ Roche lobe overflow.)

Carbon (and nitrogen) abundances, which can be used to constrain stellar evolution theory, are not well known in Galactic bulge planetary nebulae because the lines used are in the ultraviolet and are weak and difficult to measure accurately. We propose to measure the C(+) abundance in a selection of low ionization PNe where it is the dominant ion, by measuring the CII line at 157 microns. The nitrogen line at 122 microns is used in conjunction with the line at 6584 angstroms to accurately determine the electron temperature, which not only will make the nitrogen abundance more accurate, but will enable abundances to be determined for other ions measured in the visual spectrum.

Eta Carinae is a lynchpin between mass ejection of highly evolved massive stars and the enriched interstellar medium. Eta Carinae's ejecta, created in the 1840s and 1890s, is known to be nitrogen-rich with carbon and oxygen 50-100 times depleted compared to solar abundances. Most of the C,O depletion is caused by CNO processing broken by conduction from the stellar core to the outer envelope for stars greater than 60 solar masses. More depletion occurs during molecular/dust formation in the high temperature/densities of the mass ejection. From HST/STIS spectra, we have determined many iron-peak metals are greatly overabundant. It is unclear what molecules and dust form during mass ejections, and can survive in the ejecta, especially since the C, O depletions limit formation of oxides and carbides that normally precipitate onto cores of dust. Silicates and alumina grains are known to be present in the environment. This program may infer whether metallic grains are also present. 

We propose to inventory atoms and molecules in the ejected material. The Doppler velocities of this material range over +/-500 km/s in several distinct components. Although our OT1 program has not been fully observed yet, the PACS spectra in hand give hints of what can be detected with the higher HIFI velocity resolution. Emphasis will be placed on trying to understand the unusual chemistry and dust precursors arising in an exceptionally nitrogen-rich and carbon/oxygen-deficient environment. We request further HIFI scans to probe the numerous unidentified and anticipated spectral features, in particular N-bearing molecules, and to address the total mass of the ejecta.

Cir X-1 is an unusual X-ray binary in that it has large scale outbursts every 16.58 d. The cause of these outbursts is believed to be due to episodic mass transfer events that occur when a non-degenerate companion, in a highly eccentric orbit around a compact object, passes through periastron. In the 1970's, Cir X-1 was in a very luminous "high state" that resembled the outbursts of X-ray transients with black hole primaries. At this time, the maxima of the outbursts reached to K = 7.7, even though Cir X-1 is more than 5 kpc from the Sun! In the early 1980's, Cir X-1 was observed to show "Type I" X-ray bursts that indicated the compact object was a neutron star. Unfortunately, these events stopped shortly after they began, only resuming recently. In the 1990's, however, the X-ray behavior of Cir X-1 was finally confirmed to be due to accretion onto a neutron star primary. What makes Cir X-1 especially interesting is the presence of an ultra-relativistic jet. This jet is seen in both the X-ray and radio, and extends to parsec scales. There is also evidence that this jet is precessing. If true, then Cir X-1 is the neutron star counterpart to the unusual high mass X-ray binary system SS433 (where the compact primary is a black hole). We propose to obtain PACS + SPIRE photometry of Cir X-1 both in outburst, and during quiescence, to identify the dominant emission processes that occur during these phases. These observations will allow us to determine if the outbursts are due to a synchrotron jet that simply turns on during outburst or, alternatively, whether the jet is always present, but precesses across our line-of-sight once every 16 d. Precessing jets are seen in pre-main sequence stars, other X-ray binaries, and AGN. Given its extensive observational history, Cir X-1 is the ideal source for understanding the processes responsible for launching relativistic jets. Our program requests 2.5 hr of Herschel time.

Red novae are a new class of eruptive variables observed in the Milky Way and Local Group galaxies. Their eruptions are thought to be due to stellar collisions and subsequent mergers. Only recently it has been convincingly shown that one of the red novae, V1309 Sco, was a contact binary prior to its eruption. Thanks to accurate photometry from OGLE going years before the eruption we could trace the shortening of the orbital period in V1309 Sco as it was evolving toward a merger. The OGLE light curve suggests that a disk or disk-like feature was formed just before the main outburst of V1309 Sco. A disk is known to be present around another, older red nova V4332 Sgr. Such disks are expected to form during and after a merger as they accumulate angular momentum that has to be lost during the spiralling-in process. It has been suggested that from such disks 'second generation' of planets can form. This hypothesis was introduced to explain the nature of the somewhat peculiar planets, called inflated hot Jupiters. We propose to perform PACS and SPIRE photometry of the two red novae, V1309 Sco and V4332 Sgr. The far-infrared fluxes will be used to construct full spectral energy distributions of these objects, from optical to radio wavelengths. Detailed radiative-transfer modelling of the disks will determine their main parameters, i.e. mass, sizes, and dust properties. The disk parameters will be used to study the physics of a merger event. Of main interest are the disk mass and the angular momentum deposited in the star and the disk. Knowing the disk mass will allow us to test the planet formation hypothesis. By comparing the old disk of V4332 Sgr with the newly formed one in V1309 Sco, and by analysing multi-epoch variability in the disk of V4332 Sgr (the Herschel data will be compared to older Spitzer and AKARI data) we hope to gain insight on the disk formation process.

We propose to make Herschel observations of the infrared source IRAS 15099-5856 associated with a supernova remnant (SNR) detected by AKARI and Spitzer observations. IRAS 15099-5856 is the first infrared source that shows crystalline silicate features associated with a SNR or its progenitor. It offers a unique opportunity to study the mass loss and the succeeding explosion in a massive progenitor system, for which we have only little knowledge at present. Far-infrared (FIR) imaging and spectroscopic observations with PACS and SPIRE will reveal the true nature of IRAS 15099-5856 and its extended structures for the first time in the FIR and will certainly deepen our understanding of the mass loss of a massive star prior to a SN explosion.

Composite supernova remnants present us with a unique opportunity for detecting and characterizing supernova ejecta and dust as it is being illuminated by the central pulsar wind nebula. Kes 75 is a Galactic remnant consisting of a pulsar wind nebula and a partial thermal shell. It has been observed at radio, infrared, and X-ray wavelengths, but the nature of the observed emission and the progenitor star remains unknown. High absorption towards the remnant has prohibited any optical searches for supernova ejecta and has made the results from X-ray observations inconclusive. However, the 70 micron image from the Herschel Hi-GAL key project revealed emission around the pulsar wind nebula that most likely originates from the interaction of the nebula with supernova ejecta and dust. Observations with Herschel are currently the only means of detecting this ejecta and constraining the total mass of swept up gas and dust in Kes 75. We therefore propose Herschel PACS imaging and spectroscopy of the pulsar wind nebula and shell in Kes 75 in order to determine the remnant's properties and understand the nature of the supernova progenitor.

We propose to map the extended circumstellar environment of the carbon star Y CVn in the sub-mm lines of CI and CII. The high spectral resolution of HIFI will allow us to analyze in detail the line profiles and to separate the 12C from the 13C emissions. The comparison with the data obtained with the VLA in the HI line at 21 cm will allow us to disentangle the thermal broadening from the kinematic broadening. We will thus get access to the temperature profile in the circumstellar envelope and be able to constrain the cooling of circumstellar matter. The data will also provide the 12C/13C ratio and the carbon ionization state as a function of distance to the central star.

We propose to obtain PACS and SPIRE imaging observations of a sample of nearby (d<60Mpc) Seyfert galaxies. The main goal of this proposal is to understand the processes heating the dust in nearby Seyfert galaxies, including dust heated by the AGN, by on-going star formation activity, and by the general ISM radiation field. The galaxies are part of our own survey of local AGN to be observed with the mid-infrared CanariCam instrument on the 10.4-m Gran Telescopio Canarias. The sample contains 31 Seyferts of different types (1, 1.5, 1.8, 1.9, 2) and covers a large range in AGN luminosities. In this proposal we only apply for observing time for those galaxies not observed previously with PACS and SPIRE. The unprecedented angular resolution and sensitivity of the proposed PACS and SPIRE imaging observations will be used to: (1) map and quantify the on-going star formation activity across the host galaxies of local AGN, (2) obtain spatially-resolved and integrated accurate estimates of the dust temperature and content of the host galaxies, and (3) put tighter constraints on the properties of the clumpy torus by fitting their nuclear IR spectral energy distributions.

PDS456 is a southern ultraluminous IRAS galaxy at redshift z=0.18. It hosts one of the nearest powerful optically-visible AGN, and is one of the most extreme known QSOs. It is hidden behind a significant amount of optical extinction, and so its host galaxy is relatively difficult to investigate. It is know to have a very luminous, hot dust SED, and yet is not detected at submm wavelengths. We propose a Herschel PACS and SPIRE photometry observation to determine exactly the broad-band shape of its spectral energy distribution (SED), and to provide a precise determination of its bolometric luminosity. The shape of the SED will provide help in interpreting the role of the AGN and possible star-formation activity in powering this object. Without Herschel, the peak of the SED of this unique source will not be known accurately, even as an excellent understanding of its morphology, gas dynamics and astrophysical processes is built up using ground-based adaptive optics imaging, ALMA and JWST.

We propose a spectroscopic survey of the Small Magellanic Cloud (SMC) designed to measure the impact of metallicity on the interstellar medium and specifically to determine the mass and structure of molecular gas residing in a "CO-dark" phase. The SMC is the nearest truly low-metallicity, actively star-forming galaxy and shows the best evidence of any galaxy of being dominated by "CO-dark" H2 gas. This makes the SMC an absolutely unique target and the best source to study how the H2 reservoir, the relation between star formation and H2, and the relation between H2 and CO are affected by metallicity. These are key problems with far-reaching implications for the evolution of the star formation across cosmic time and the interpretation of high-redshift observations in the ALMA era. Our survey consists spectral mapping with FTS+PACS ([CII], [OI], [NII], [OIII]) of 5 regions selected to span a wide range in relevant parameter space and enable a clean and precise measurement of the abundance of "CO-dark" molecular gas. This rich dataset will have lasting legacy value and address a key gap in the Herschel legacy, enabling studies in a wide range of other topics. Moreover, the coIs will publicly distribute the data products 18 months after the end of observations. The team have extensive leading expertise on these science topics, as well as modeling and data reduction.

We propose to obtain PACS and SPIRE photometry of 39 early-type galaxies (ETGs) with molecular gas maps from the Atlas3D survey. These data will allow the spatially-resolved relations between molecular gas and star formation (i.e. the star formation law) and radio continuum and FIR emission to be studied in a large sample of ETGs for the first time. We will determine whether ETGs follow the same relations as found in late-type galaxies and if not, consider what galaxy properties correlate most with their deviations (stellar mass, environment, bulge-to-disk ratio). The Atlas3D survey is the perfect survey to do this for, with a wealth of data and analysis available for all sample galaxies, including CO, HI and radio continuum interferometry which are critical to this work. Another aim of this proposal is to constrain the proportion of dust heated by old stellar populations in ETGs. Even in star-forming ETGs, the specific star formation rates are low, making this an even bigger concern than for spirals. Thirdly, these observations will constrain the origin of dust and gas in ETGs via the dust-to-gas ratio (low ratios imply gas accretion from an unenriched source). Our previous results suggest a strong dependence of gas accretion history on environment, with external accretion being important in the field only. In this case, we expect all cluster galaxies to have high dust-to-gas ratios, but a more varied assortment in the field galaxies. The Herschel data will allow us to test this hypothesis.

We propose Herschel observations of the CO Spectral Line Energy Distribution (SLED) in a sample of seven local (z < 0.1) radio galaxies with the highest CO(1-0) luminosities. These radio galaxies fall into two classes in terms of their infrared (IR)-to-CO luminosity ratio, or ``star formation efficiency'' - those with high IR/CO similar to IR luminous starburst galaxies, and those with low IR/CO ratios comparable to low luminosity spiral galaxies. The observed dichotomy in IR/CO likely represents (1) intrinsic differences in the star formation efficiencies within the sample, (2) an enhancement in the infrared luminosity of the galaxies with high IR/CO by AGN dust heating, (3) or inaccuracies in the star formation efficiency determinations introduced through the use of a constant CO luminosity-to-molecular gas mass conversion factor, or through the use of CO(1-0) to trace the molecular gas actively involved in star formation. With the Herschel Spire FTS, we will detect high-J (>5) rotation CO transitions, enabling (1) an accurate determination of the star-forming molecular gas mass, temperature and density, and thus a more accurate estimate of the star formation efficiency, (2) an assessment of the effect AGN and starbursts have on the excitation of the high-J CO transitions, and possibly of H2O and OH lines. In addition, we will make use of our data in concert with the HERCULES dataset to (3) determine whether the high-J CO transitions scale with far-IR luminosity, and are therefore useful tracers of the star formation rates of radio galaxies. These observations will provide, for the first time, a truly robust insight into star formation and AGN heating of gas in radio−selected, AGN−dominated environments. In addition, the analysis will be applicable to the interpretation of high−J CO emission from high redshift AGN hosts done with Herschel and ALMA.

We propose imaging with PACS (70+160 mciron) and SPIRE to ensure full resolved far-infrared (FIR) spectral energy distribution (SED) coverage of a complete equatorial sample of star-forming galaxies. This sample consists of every equatorial, face-on, star-forming galaxy of large angular extent and luminosity larger than M33. Because of their accessibility to all major facilities, particularly ALMA and the EVLA, these are the natural targets of the next generation of local galaxy studies. Herschel data are critical to estimate star formation rates, dust masses, and energetics in these galaxies and no comparable coverage of the IR SED will be possible in the foreseeable future. Without our proposed program only 13 of the 67 galaxies in this key sample will have high resolution data that span the IR peak, hindering studies of the life cycle of dust, dependence of star formation on host galaxy and local conditions, and development of robust calibrations of star formation rate tracers and the CO-to-H$_2$ conversion factor. Observations of this sample therefore would represent a key part of Herschel's legacy and significantly enhance the nearby galaxy science from the next generations of northern and southern telescopes. In order to ensure maximal yield from both Herschel and ALMA/EVLA, we commit to waive our proprietary period and rapidly release our reduced data products.

We request 78 hours of observing time to obtain 5-10 sigma detections of the [CII]158um line for a complete sample of 103 star-forming galaxies with 9.0<log(M*/Msun)<10.2 . These observations form the bedrock of an ambitious new program to understand the gas accretion and star formation histories of low mass galaxies in the local Universe. In this stellar mass range, galaxies are dominated by cold gas rather than stars, gas-phase metallicities drop below solar, and CO line luminosities quickly become a poor proxy for the total molecular gas content of a galaxy. We note that the majority of star-forming galaxies in the high redshift Universe (z>2-3) likely lie in this regime, irrespective of their mass. By measuring [CII] line fluxes with Herschel/PACS, our hope is to disentangle variations in CO line flux measurements that might arise because galaxies have different gas accretion histories, from systematics in the CO-based molecular gas measurements resulting from changes in the structure and chemical compositions of the molecular clouds themselves. The majority of galaxies in our sample already have HI data from Arecibo. Total star formation rates and stellar masses have been estimated using multi-band GALEX and SDSS photometry. We are simultaneously applying for IRAM 30m telescope time to obtain CO line fluxes, and MMT time to obtain long-slit spectroscopy to estimate gas-phase metallicity and dust extinction profiles for the galaxies in our sample. At the very least, by tracking the [CII]/CO ratio as function of stellar mass, SFR and metallicity, we will empirically (and hence robustly) determine the global properties of galaxies for which the standard XCO factor no longer provides accurate total molecular gas masses. This will be crucial input to future studies of CO in high-z galaxies.

Recent studies in galaxy evolution have uncovered a tight "main sequence" (MS) of star-forming galaxies that evolves with redshift. We propose to obtain Herschel FIR photometry for 100 galaxies from the S5 galaxy sample (Spitzer SDSS Statistical Spectroscopic Survey)---the largest optically selected sample of galaxies with Spitzer mid-IR spectroscopy---in order to test and improve our understanding of this MS. We will derive accurate IR luminosities, dust temperatures, dust masses and derived star formation rates for a representative sample of normal star-forming galaxies extending up to 2 sigma above and below the MS at z~0.07. In combination with the extensive multi-wavelength data that exists for the S5 sample, PACS/Herschel photometry will provide the critical, final piece of the puzzle that we need to track the evolution of physical parameters across the main sequence. Furthermore, we anticipate that this survey will produce a unique data set that will connect Herschel studies of local and distant galaxies to the vast archival resource of SDSS and corollary observations.

Edge-on spiral galaxies are a unique perspective on the vertical structure of spiral disks, both stars and the iconic dark dustlanes. The thickness of these dustlanes can now be resolved for the first time with Herschel in far-infrared and sub-mm emission.

Resolved far-infrared and sub-mm observations of edge-on spirals will impact on several current topics. First and foremost, these Herschel observations will settle whether or not there is a phase change in the vertical structure of the ISM with disk mass. Previously, a dramatic change in dustlane morphology was observed as in massive disks the dust collapses into a thin lane. If this is the case, the vertical balance between turbulence and gravity dictates the ISM structure and consequently star-formation and related phenomena (spiral arms, bars etc.). We specificaly target lower mass nearby edge-ons to complement existing Herschel observations of high-mass edge-on spirals. Secondly, the combined data-set, together with existing Spitzer observations, will drive the generation of spiral disk Spectral Energy Distribution models. These model how dust reprocesses starlight to thermal emission but the dust geometry remains the critical unknown. And thirdly, the observations will provide an accurate and unbiased census of the cold dusty structures occasionally seen extending out of the plane of the disk, when backlit by the stellar disk.

We ask for priority one for the remaining 8.9 hours of PACS and SPIRE observations of low- and intermediate-mass disks complement slated Herschel observations of massive edge-on spirals and existing Spitzer observations in the near-infrared.

The tidal features produced by gravitational interactions between galaxies may contribute significantly to the enrichment of the intergalactic medium in dust and heavy elements. However, at the present time little is known about the dust content and properties of tidal structures. To address this lack, we propose to use the PACS and SPIRE instruments on Herschel to image a sample of nine nearby interacting galaxies in six far-infrared/submm broadband filters. We will map the dust column density and temperature in the main bodies and tidal features of these galaxies, and compare the far-infrared/submm properties of these features with those of normal spirals and dwarf galaxies. We will compare the Herschel maps with already acquired GALEX UV, Spitzer IR, and ground-based optical data, and with population synthesis and radiative transfer codes, to investigate dust heating mechanisms and extinction in these galaxies. We will compare with available radio maps to investigate dust/gas ratios and star formation triggering mechanisms, and compare with numerical simulations of the interactions. Our sample includes the closest and best-studied examples of tidal dwarf galaxies and accretion-driven star formation. These will provide a good testbed for interpreting high redshift systems.

We propose for PACS spectroscopy of the [O III] 88 micron and [N II] 122 micron lines, and SPIRE far-IR photometry, to observe a sample of 16 low-redshift IR-luminous galaxies, at log L_IR = 11.6 to 12.2 Lsolar, that are distinguished by large size and non-merger structure. In OT1 we are obtaining PACS spectra of [C II] 158 and [O I] 63 microns for this sample. These galaxies are interesting because they have high SFR activity spread over a large physical area, rather than concentrated into extremely dense nuclear regions, as in most local major merger ULIRGs. They are good analogs for high-redshift IR-luminous galaxies, which have far-IR spectral shapes different from local ULIRGs. At z>1, much of the star formation in massive galaxies is at LIRG and ULIRG levels, and U/LIRGs dominate the IR luminosity density. Understanding star forming regions in high-z IR-luminous galaxies is necessary to understand the conditions in which most of the stars in massive galaxies formed. In a few high-z lensed ULIRGs where [C II] can be observed, [C II]/FIR is high, like local star-forming galaxies and unlike local ULIRGs. [C II] is a major cooling line in PDRs and the far-IR lines probe the physical conditions and UV intensity in IR-emitting regions. In our sample observed so far in OT1, [C II]/FIR is high - they do not suffer the "[C II] deficit" found in local ULIRGs. This suggests that redshift evolution in IR SEDs and line ratios are related to the larger extent of star formation, and that this low-z disky sample are good analogs. The [O III] and [N II] lines provide more detailed probes of the ionization state, gas density, and ionizing SEDs in the star-forming regions: in published samples the [O III]/FIR ratio shows tension with simple models for the line deficit, and [N II] and [O III] can constrain ionizing SED versus gas density. The SPIRE far-IR photometry will constrain the total IR luminosity and cold dust in these galaxies, which have cool IR colors and far-IR fluxes rising past 100 microns.

Herschel observations have revealed an excess (over the expectations of naive models of dust emission) of long-wavelength emission in many regions of the Magellanic Clouds. We propose to determine the nature of this excess by measuring select regions at higher spectral resolution using the SPIRE FTS. Our measurements will demonstrate whether emissivity changes, spinning dust, cold dust, or line emission are the cause of the excess emission observed at long wavelengths.

Our Herschel key project "The Dusty Young Universe" observed 71 quasars at the highest redshifts (z > 5) with PACS and SPIRE. Similar to the local universe we find that the hottest, AGN heated dust shows a flat or slightly rising spectral energy distribution in nuF_nu between 24mu (Spitzer) and PACS 100mu (i.e. rest-frame 3.4mu < lambda_rest < 14mu at z=6). However, in the course of the project we identified some exceptional cases that are undetected by PACS at 100mu. Their upper limits result in nuF_nu(100mu) < 0.8*nuF_nu(24mu) indicating a deficit of cooler dust below T ~ 300 K. Such cases are not known among AGN in the local universe and seem to require a very compact central dust distribution. Here we propose to re-observe the best six of these exceptional quasars with PACS at 100 and 160mu with a threefold integration time in order to reach a factor of 2 deeper in flux when combining with the already acquired data. Both a successful detection or a substantially lowered upper limit will allow us to determine the temperature of the hot dust better and estimate its total mass. The small radius of the dust distribution might indicate dust production near the quasar core. PACS on Herschel is the unique facility to investigate the apparent differences of the dust distributions in quasars between the young universe and today.

AGN-powered feedback of energy and momentum via radiation pressure ("quasar mode") on interstellar dust and jet momentum ("radio mode") from a supermassive black hole (BH) into its host galaxy regulates the evolution of both the BH and the galaxy. Feedback is likely to be strongest in the most luminous dust-obscured QSOs, particularly those containing radio sources too luminous to be powered by starbursts. We selected a unique sample containing 147 of the most luminous obscured QSOs in the universe by identifying strong mid-infrared sources from the WISE survey covering more than half the sky having (1) convex mid-infrared spectra and (2) bright NVSS radio counterparts. The goal of our multi-telescope program is to understand the physical and evolutionary nature of these extreme feedback candidates. We have high priority (top decile) ALMA Cycle0 time for the southern sources in the sample for imaging at 345GHz, and SOAR time to obtain redshifts. This proposal requests 47.6 hours of PACS and SPIRE time to determine the relative warm to cool dust luminosities in these 147 sources, key observations for determining the relative AGN and starburst luminosties, and understanding the evolution stages, of these likely transition objects. Our goals are to discover the most obscured and powerful BHs throughout their main epoch of formation, and to test and constrain the roles of radio and radiative feedback in the quenching of star formation and the establishment of the BH-spheroid relations.

We propose to map a complete sample of 88 local star-forming major-merger pairs (median redshift 0.04), using PACS and SPIRE photometers in 6 bands at 70, 100, 160, 250, 350 and 500 micron. The goal is to set the local benchmarks for the cosmic evolution of the SFR-to-gas relation (the Kennicutt-Schmidt law) for major-merger pairs, complementing a study on the K-S law for high-z mergers in the COSMOS field using the PEP and HerMES data. The K-S law for major mergers may be significantly different from that for normal galaxies. The SPIRE imaging at 250, 350, and 500 micron, together with PACS maps at shorter wavelengths, will probe the gas mass estimated from the dust mass. Dust is arguably the best proxy for total gas in galaxies spanning a wide redshift range, given the fact that it is still impossible to observe the HI gas in high redshift galaxies through the 21cm line emission. The PACS imaging at 70, 100, and 160 micron will map the star formation in these systems, with good angular resolutions (6 -- 12 arcsec) and at the wavelengths near the peak of the infrared dust emission. The local sample closely matches the high-z COSMOS pairs sample (278 pairs) in the pair selection criteria, both being stellar mass selected and including only spiral-spiral (S+S) and spiral-elliptical (S+E) major-merger pairs. This will facilitate studies on stellar mass dependence of the K-S law for major mergers with different redshifts. The large sample size enables good statistics even after separating the sample into subsamples of S+S pairs and of S+E pairs, and into several mass bins.

We propose PACS 70um and 160um photometry of 5 post-starbust galaxies selected from the SDSS and detected in the Spitzer MIPS 24um channel. We will measure the temperature of the FIR dust continuum and determine the contribution of enshrouded star formation to the observed 24um luminosity. This measurement, in combination with optical and NIR spectroscopy will allow us to constrain the bolometric contribution of TP-AGB stars to these galaxies. By doing so, we will constrain the TP-AGB as a systematic bias for MIR measurements of star formation and AGN and determine the extent to which TP-AGB stars must be taken into account when inferring stellar masses from observed luminosities and colors of galaxies. The observations will consume 9 hours of spacecraft time for these 5 objects, and we will leverage this time by employing photometry from the Herschel archive for one additional source and considering the impact of 7 other post-starburst galaxies with MIPS upper limits. This gives us a total sample of 13 galaxies to determine the importance of the TP-AGB as a function of burst age and strength and to extrapolate from our sample to a more extensive range in star formation histories.

We propose observations, using SPIRE at 500 micron, 350 micron and 250 micron, of a sample of galaxies showing the phenomenon of counterrotation (gas vs. stars and/or stars vs. stars). Our targets span all the morphological sequence and the sample is composed by all the galaxies with counter-rotation in the local volume of 10Mpc. Our aim is to derive, for the first time, the sub-mm emission of such galaxies. Our simulations of galaxy evolution, that include spectro-photometric evolutionary population synthesis (EPS) accounting for dust effects, are able to predict the whole spectral energy distributions (SED) of a galaxy at different epochs together with the dynamical properties of all the system components. As explained in the following, these new data combined with our model will allow us to constrain the SEDs giving not only insight into the properties of the dust (temperature, mass and distribution) but also the age of the galaxy or the merger that originated the counter-rotation.

We propose to set some of the first robust constraints on the power source in IR-luminous galaxies at 3<z<5, via PACS photometry of ten sources in this redshift range. All of our targets are far-IR selected, have secure SPIRE detections, and spectroscopic redshifts from intensive ground-based followup. None of them are classical QSOs. The 3<z<5 redshift range is a crucial one for understanding the role that IR-luminous galaxies play in driving galaxy evolution. The rates of stellar and SBMH mass assembly must have increased by a factor of at least 5 during this epoch, with a substantial fraction of this increase thought to occur in obscured, luminous `bursts'. Despite this, determining the power source in z>3 IR-luminous systems has been hard; they are difficult to find high spatial resolution counterparts for, and require both mid- and far-IR photometry to deconvolve their SEDs and extract starburst and AGN luminosities. The PACS data proposed for here will be sensitive to even moderately IR-luminous AGN in our sample. In combination with the SPIRE data, which is sensitive to obscured star formation, we will set tight constraints on the power source behind the IR emission in our sample. This, in combination with previous results, will provide important information on the evolution of the power source(s) in IR-luminous galaxies with redshift across most of the history of the Universe.

We will use PACS scan maps to measure the 100 and 160 micron flux of I Zw 18, the lowest metallicity galaxy within 20 Mpc. I Zw 18 offers a nearby window into to the processes which make stars in the primitive galaxies observed in the high redshift Universe. We will measure the dust mass of I Zw 18, and combine this with data already in hand to determine its dust-to-gas ratio, yielding *the* crucial measurement to establish how dust-to-gas ratio relates to metallicity in galaxies. Measuring the dust mas of I Zw 18 requires to accurately constraint of the long wavelength side of the dust infrared spectral energy distribution. Existing data has proven unsuccessful at detecting this galaxy longwards of 70 um. Our observations are designed to detect I Zw 18 at 100 um and either detect it or yield a strong constraint at 160 um. With a very modest time investment (under 5 hours) these measurements will determine whether the dust-to-gas ratio is linear or superlinear with metallicity. Because the dust-to-gas ratio is related to the formation and destruction of molecules and the heating of the ISM, this is a key measurement to understand the impact of metallicity on the evolution of galaxies.

Dust affects the cooling cycle in the ISM and this affects the ability of a galaxy to form cold, dense clouds that can form stars. Thus, the low dust content of dwarf irregular galaxies should have consequences to the star formation process, but just what is the connection? We propose to use SPIRE and PACS to map the FIR dust continuum emission of 5 dwarf galaxies, specifically extending the sample of nearby resolved dwarfs being observed under KP/GT/OT1 programs to 5x lower metallicities. We will construct spatially resolved FIR spectral energy distributions and determine the dust components. That, in combination with our exquisite HI maps and comprehensive images tracing star formation over three age scales, will allow us to examine the relationship between the dust content, gas, and star formation in dwarf irregular galaxies as a function of metallicity. These data will be unique in the wealth of information they will provide about dust at very low metallicities, and this will be important for understanding the formation of stars in the early universe.

Eight billion years ago, at z~1, the star formation rate (SFR) in the universe peaks and the vast majority of galaxies are blue with the plurality being luminous compact blue galaxies (LCBGs). Today, the SFR is an order of magnitude lower, galaxies are evenly divided between a red and blue sequence, and LCBGs are extremely rare. It remains unclear as to what has caused star formation to be quenched in galaxies in general, and specifically in LCBGs. Since LCBGs reside at the high mass end of the blue sequence, they are poised to have their star formation quenched in the near future. As such, they are a unique laboratory for studying how galaxies evolve from the blue to the red sequence. We are proposing to use PACS and SPIRE photometry to measure the SFR and dust mass for 52 local LCBGs in order to constrain the duration of their current starburst. Combined with multi-wavelength archival data, we will identify which LCBGs are having their star formation quenched and determine how these galaxies will evolve.

Herschel has provided unprecedented insight into the properties of the ISM of local Ultraluminous Infrared Galaxies (ULIRGs) and high redshift submillimetre bright galaxies. Although matched in luminosity the ISM properties of the two samples are markedly different. We propose to exploit the wide wavelength coverage of SPIRE-FTS to study far-infrared fine structure cooling lines from a unique sample of 23 intermediate redshift ULIRGs. Our targets span the redshift range 0.2 < z < 0.8 and luminosity range 12 < log L(IR) < 13 and have been selected from the Herschel Multi-tiered Extragalactic Survey (HerMES) with excellent ancillary data. The redshift range has been chosen so that we can simultaneously detect key cooling lines [CII] 158 microns, [NII] 205 microns and [CI] 371 microns in all of our targets. Our sample is suitably selected to link the properties of the ISM near and far: it is at these intermediate redshifts where the change in the properties of the ISM takes place. Using the proposed observations we will: 1) investigate the properties of the ISM of ULIRGs at a redshift where they contribute dominantly to the total IR energy density; 2) search for changes in the ISM as a function of luminosity and redshift; 3) explore metallicities (through [CII]/[NII] ratio) and investigate the validity of [NII] as a star formation indicator; 4) address the effect of the AGN in the surrounding ISM. To complete our goals we request observations for a sample of 23 ULIRGs. Herschel is currently the only facility capable of addressing these important questions.

SPIRE photometry is proposed for the 156 most infrared-luminous quasars with 1.5 < z < 5 to determine accurate total infrared luminosities and evolution of luminosity and dust temperature. Sources are chosen using new mid infrared measures with the Wide Field Infrared Survey Explorer of quasars from the Sloan Digital Sky Survey. SPIRE will measure all quasars in this redshift range at rest frame 80 micron, near the luminosity peak, and will give full SEDs from rest frame ultraviolet to far infrared when combined with WISE and SDSS data. Results can be compared to existing archival results for the most luminous, heavily obscured, type 2 quasars discovered with Spitzer and contained in Herschel key project survey fields.

H2O and OH are key tracers of the structure, kinematics, and activity in the nuclear regions of (Ultra) Luminous Infrared Galaxies (ULIRGs): with their excitation dominated by pumping by far-infrared continuum radiation, they probe the nuclear source of the far-IR radiation and its associated structures (disks, torus); their P-Cygni, absorption, and emission profiles trace massive molecular outflows and possibly inflows, and the astrophysically important associated energetics involved in the (negative) feedback from star formation and/or AGN on the molecular gas; they probe the physical and radiative environments (X-rays, cosmic rays, hot cores) where they reside. In order to distinguish among the above scenarios, we propose PACS spectroscopy of key transitions of H2O and OH in a sample of 9 bright (U)LIRGs where submillimeter H2O lines have been detected with SPIRE, as well as key diagnostic lines of NH3 and OH+ to ascertain the formation mechanism and implied physical processes. The proposed observations will serve as a crucial benchmark for future routine observations of H2O with ALMA in the distant Universe.

We propose to exploit the spectroscopic capabilities of PACS to describe the [C II] line emission in a unique and comprehensive sample of star-forming galaxies selected from the wide-field, parallel PACS+SPIRE H-ATLAS imaging survey.

The sample has exquisite optical spectra from GAMA and SDSS, allowing us to:

[1] describe [C II] line as a function of dust and stellar mass, metallicity, extinction, dust temperature, and many other physical parameters; [2] identify the parameters controlling the behaviour of [CII]/L(FIR) at log L(FIR)>11; [3] calibrate [CII] as a star-formation indicator [exploiting our accurate L(FIR) and L(Halpha)] and determine the range over which it is valid.

[CII] is potentially an unrivalled tracer of the total gas mass in galaxies (in theory better than CO), and it is therefore an increasingly important observable, e.g. for upcoming ALMA observations of distant galaxies. Our study will become the benchmark for the interpretation of high-z observations, with a legacy value that will survive well into the SPICA era.

Some of the key advantages of this proposal over previous Herschel studies such as SHINING and HerCULES are:

- we cover 10.2 < log L(FIR) < 11.5 and are unbiased towards powerful ULIRGs with complex merger morphologies; - our sample is selected blindly from H-ATLAS rather than from IRAS, and thus allows exploration of comprehensive parameter space and is much less biased towards galaxies with warm dust emission; - we know the spatial extent of the galaxies, allowing reliable flux measurements via a single pointing within 10 min/target.

We can thus achieve our goals in a systematic fashion, maximising the parameter space for the diagnostics of interest.

We stress that the scientific legacy of ISO and Spitzer has in large part been based on the wealth of data in their spectroscopic archives and the same will likely be true for Herschel.

We propose a survey of PACS (at 70 and 160 micron) and SPIRE (at 250, 350 and 500 micron) imaging of a sample of 31 of the most turbulent and intensely star forming galaxies in the local universe to measure their characteristic dust temperatures, dust masses and total infrared luminosities. These galaxies, selected from the all sky SDSS survey as the most H(alpha) bright galaxies in the nearby universe, have high velocity dispersions but show signs of ordered disk rotation (Green et al 2010) and as a consequence have more similarities to high-redshift turbulent disk galaxies than dynamically-relaxed galaxies common to the local universe. But are these truly low redshift analogues of turbulent rotating disks or are they currently undergoing a starburst episode? While both galaxy types are expected to be bright in the infrared, the former would have a much lower characteristic dust temperature that can efficiently be measured with Herschel due to the proximity (0.06<z<0.25) of these galaxies.

We propose to investigate the presence of ram pressure-induced shocks in three Virgo cluster galaxies exhibiting clear evidence for on-going ram pressure stripping, from a wealth of radio continuum, optical, infrared, and HI data. To achieve our goals, we will perform PACS spectroscopy to measure the [OI] and [CII] emission line strengths of three outer-disk regions. These regions are precisely located along the leading edge of the interaction region between the hot intracluster medium (ICM) and the cooler galaxy interstellar medium (ISM). The ionization state of the ISM gas within the leading edges will be revealed by the ratios of these two emission lines since they are the dominant coolants in the neutral and ionized ISM at low temperatures. Previous Spitzer IRS observations hinted at the presence of shock-excited molecular hydrogen. Hence, these proposed PACS spectroscopic observations will provide independent confirmation of ram pressure-induced shocks in the cold ISM along the leading edges of these ram pressure-stripped galaxies. Evidence for shock excitation throughout the ISM may explain the enhanced, global radio/infrared ratios observed in galaxies that are experiencing strong ram pressure.

We propose deep PACS and SPIRE imaging for all (6) normal, edge-on (i >85 deg) galaxies with d<10Mpc as part of the Herschel EDGE-on galaxy Survey (HEDGES). These data will allow us, for the first time, to characterize variations in the far-infrared (FIR) spectral energy distribution (SED) among and within halos for an energetically diverse sample of nearby, edge-on galaxies as a function of height above the disk. The proper sampling of the halo dust SEDs (i.e., 6 bands between 70-500um), will allow us to take inventory of the dust content of halos and illuminate the signatures of dust processing imprinted in the dust SED and its variations. These observations will provide a way to address a number of outstanding questions related to the processes governing the interchange of disk/halo material such as: (1) How does halo dust content relate to disk star formation activity? (2) What are the physical characteristics of halo dust (i.e., temperature(s), mass, emissivity, PAH mass fraction, and what does their variation with height from the plane tell us about grain modification by the energetic processes responsible for disk-halo cycling? (3) What can dust and radio continuum halos tell us about transport effects that are important for understanding the FIR-Radio correlation? (4) How does the distribution of halo dust compare to that of other gas tracers, and hence what can we learn about how such dust is associated with various gas phases? The HEDGES sample galaxies have a treasury of ancillary data (e.g., radio, Spitzer, optical, gas), and the addition of these deep Herschel data will make HEDGES the definitive sample to study multi-phase disk/halo feedback processes arising from the accretion, expulsion, and/or cycling of material between disks and halos into the foreseeable future.

The basic theoretical picture of hierarchical structure formation is well supported by observations. Within this scenario, large galaxies assemble from smaller ones, and such mergers are most common in galaxy groups that are themselves in the process of falling into even larger clusters. However, little is known about the ultimate fate of the primordial gas that is used to fuel the formation of these galaxy groups. Does all the metal-free gas get consumed in galaxies and reprocessed? If the gas is left outside of galaxies in the intragroup medium, is it ionized on timescales too short to be detected at the current epoch? Is any left behind pristine and untouched? To answer these questions, which are crucial for a complete picture of galaxy formation and evolution, we propose for confusion-limited mapping of the entire (2 x 2 deg) Leo Ring in all three SPIRE bands to search for cold, low surface brightness dust emission. At 10 Mpc and 200-kpc in diameter, the Leo Ring is the only known HI cloud for which a primordial origin has not been ruled out. A firm cold dust detection would eliminate the possibility of a primordial origin for the Ring. Alternatively, a non-detection would place a strict upper limit on the dust-to-gas ratio an order of magnitude lower than has been observed for nearby low-metallicity systems, and thus would make a tidal origin highly unlikely. If the far-infrared SPIRE flux measurements lead to a conclusion that the gas is primordial, the Ring will be the first known instance of HI gas left unprocessed and not yet ionized after the formation of a galaxy group, and offers a unique snapshot of galaxy formation in action.

The assembly of star forming molecular clouds is poorly understood in low metallicity galaxies. These galaxies are typically forming stars, and thus must have molecular gas, yet they almost universally lack direct detections of CO. As an alternate means to trace the molecular component of these systems, we propose to use the PACS and SPIRE instruments aboard Herschel between 100-500 microns to image the cold dust distribution and determine the temperature of the dust in 4 nearby low metallicity galaxies drawn from the VLA-ANGST sample. VLA HI spectral line observations for these galaxies have exceptional spectral resolution (0.65 - 1.3 km/s) which allows us to reliably decompose the spectra into narrow and broad components which have been associated with the cold and warm neutral gas phases. Coincidence of cold dust detected by Herschel with narrow HI spectra will both confirm the existence of a cold neutral medium as well as define the areas most conducive for molecular cloud formation. Combining the proposed Herschel observations with existing HST, VLA, and SPITZER observations will allow us to separate local regions currently forming stars from those which have yet to form them. Understanding the local conditions which are most likely to form molecular clouds is extremely important to the general understanding of star formation, molecular cloud formation, and galaxy assembly/evolution. If our proposed observations confirm that the narrow HI emission is an effective tracer of the more elusive molecular component, then we will have calibrated a method which is generally applicable for all nearby low metallicity galaxies.

The assembly of star forming molecular clouds is poorly understood in low metallicity galaxies. These galaxies are typically forming stars, and thus must have molecular gas, yet they almost universally lack direct detections of CO. As an alternate means to trace the molecular component of these systems, we propose to use the PACS and SPIRE instruments aboard Herschel to observe both the 158um CII emission line and the cold dust emission between 100-500 microns in the nearby low metallicity galaxy, Sextans A. Recent VLA HI spectral line observations of Sextans A have exceptional spectral resolution (1.3 km/s). This high velocity resolution allows us to reliably decompose the spectra into narrow and broad components which have been associated with the cold and warm neutral gas phases. Coincidence of 158um CII and cold dust emission detected by Herschel with narrow HI spectra will both confirm the existence of a cold neutral medium as well as define the areas most conducive for molecular cloud formation. Combining the proposed Herschel observations with existing HST, VLA, and SPITZER observations will allow usto separate local regions currently forming stars from those which have yet to form them. Understanding the local conditions which are most likely to form molecular clouds is extremely important to the general understanding of star formation, molecular cloud formation, and galaxy assembly/evolution. If our proposed observations confirm that the narrow HI emission is an effective tracer of the more elusive molecular component, then we will have calibrated a method which is generally applicable for all nearby low metallicity galaxies.

Simulations of structure formation and evolution suggest that feedback is critically important to the evolutionary paths of galaxies and their supermassive black holes. However, while high velocity outflows have been routinely detected in the ionized winds of many powerful AGN, it remained unclear whether this momentum was being effectively transferred to the neutral and molecular gas that actually form stars. Several recent observations over the past year have finally provided some breakthroughs in this regard: in particular the neutral NaD and molecular OH and CO components in the warm quasar-dominated merger Mrk 231 have all been shown to have >1000 km/s outflows from the nucleus, indicating momentum transfer well in excess of what could be produced by the ongoing star formation alone. Several more ULIRGs are under similar investigation to broaden these important results and understand how this feedback might scale with relative AGN strength, merger stage, availability of fuel, etc. Somewhat surprisingly, these samples include none of the most powerful (i.e., ``hyper'') luminous infrared galaxies (HLIRGs). ``Local'' HLIRGs are 3-10x more powerful than Mrk 231 and their bolometric output is almost always AGN-dominated. As such, HLIRGs can extend studies of how AGN power affects feedback by an order of magnitude. Here we propose to look for trends between the basic measured properties of OH (incidence of absorption, kinematics, column densities) and host/evolutionary indicators in a sample of 5 powerful HLIRGs.

Stars form in dense, cold clouds of molecular hydrogen (H2), best observed in lines of the tracer carbon monoxide (CO). As stars turn on, the dense gas is heated, ionisation occurs, and a photon-dominated region (PDR) is formed. Here, CO dissociates to neutral carbon, much of which is subsequently ionized. Both neutral and ionized carbon cool the interstellar gas by strong line emission at far-infrared/sub-millimeter wavelengths. Thus, CO emission is a good tracer for cold and dense, [CI] for warm dense, and [CII] for warm tenuouis gas. Cold tenuous gas is traced by neutral atomic hydrogen emission.

Galaxies have different metallicities and gradients, strongly affecting the physical processes ruling the heating and cooling of the interstellar medium (ISM). In order to understand the ISM in distant galaxies, we need to understand how metallicities and radiation fields affect ISM physics. By observing the ISM in the low-metallicity Large and Small Magellanic Clouds, the response of the ISM to various radiation fields is gauged as a function of the very different metallicities of the SMC, the LMC, and the Milky Way.

We have selected in the LMC and the SMC interstellar clouds exposed to a range of radiation field intensities. Ideally, we would fully map these clouds, but time constraints limit us to strips in lines requiring long integration times: the 1.9 THz [CII] and 809 GHz [CI] lines, which are in effect unobservable from the ground, requiring Herschel space-borne observations, to complement a series of CO and [CI] (492 GHz) observations from the ground. Together with HI maps, they will provide us with the carbon and hydrogen budgets, and determine, in detail, the distribution of the various carbon phases over a wide range of phyical conditions. Analysis of the HI/[CI]/[CII]/CO/H2 interfaces is well-feasible thanks to the advanced ISM/PDR codes developed by members of our team.

The powerful radio galaxy Cygnus A affords the opportunity to study the activity of a hidden quasar at high spatial resolution. We have modelled the optical through radio SED of Cygnus A using data from a dedicated Spitzer spectroscopy program (Privon et al 2011). Our primary aim was to constrain the relative contribution of AGN and star formation heating to the total energy budget of the source. Our analysis also reveals that there must be a break in the synchrotron spectrum at FIR/sub-mm wavelengths. However, the paucity of data from 70-500 mu limits our ability to define the synchrotron component and the physical decomposition of the SED. We propose a 3hr program of observations with PACS and SPIRE to precisely define the far-infrared emission of Cygnus A between 50 and 700 microns. This will provide tight constraints on the far infrared emission and enable us to accurately model the contirbution of embedded star formation to the infrared luminosity. This in turn will provide an improved determination of the bolometric AGN luminosity, the geometric properties of the obscuring torus, and the behavior of the synchrotron spectrum at infrared wavelengths. We have in place a comprehensive suite of Bayesian SED modelling codes to analyse the data.

The Herschel Reference Survey (HRS), the first unbiased survey of dust in early-type galaxies (ETGs), has provided insights into the evolution of both S0s and ellipticals. The small dust disks in S0s suggest that these galaxies are early-type spirals that have had their dust and gas removed by environmental processes such as ram-pressure stripping. The properties of the dust in the ellipticals imply that the dust in these has been acquired by gravitational interactions - a process that is likely to be more important in low-density environments. Although the optical properties of ETGs do not depend strongly on environment, in contradiction to the hierarchical paradigm, our results suggest that there should be a clear environmental signature in the properties of the dust. The volume of the HRS, however, is dominated by the Virgo Cluster, and so contains few ETGs in genuinely low-density environments. As a collaboration between the HRS and ATLAS3D teams, we propose to carry out an efficient Herschel survey of the much larger ATLAS3D sample, providing a legacy survey of four times as many ETGs as are in the HRS and extending our original survey to much sparser environments. Apart from its legacy value, we will answer four questions: 1) Are the small sizes of the dust disks in S0s the result of a current environmental process? 2) How do the properties of the dust in ETGs depend on the mass of stars in the galaxy? 3) Do the dust properties of the ellipticals display the clear environmental signature that the hierarchical paradigm requires? 4) How do the dust properties of the ETGs depend on the specific angular momentum of the stars, which has been measured for the ATLAS3D galaxies and may be more revealing of the basic physics of ETGs than the morphological classification of ellipticals and S0s?

We propose to study the properties of dust in elliptical galaxies. The interstellar environment of elliptical galaxies is characterized by the dominance of hot plasma and old stellar radiation fields with little UV. Dust in hot plasma is easily destroyed by sputtering, while old stars cannot replenish a large amount of dust into the interstellar space. Despite such hostile conditions, many elliptical galaxies contain a considerable amount of dust. Our goals are to identify the supplying sources of dust and to understand interplay between dust and hot plasma. We selected 6 galaxies from the AKARI sample, which were found to be extended in the far-IR with AKARI. But its spatial resolution was too poor to discuss the detailed structures of the dust emission. Herschel is the only facility which enables us to discuss them. Our studies are based on two kinds of Herschel data: PACS imaging with the finest resolution and PACS-SPIRE SED mapping with a coarser resolution. Using the former data, we spatially decompose the dust distribution into a stellar distribution, a dust lane, a central point-like source, and the other. We derive the fraction of each component to the total emission. The last component may represent clumpy clouds in outer regions or structures extending from the center, which are compared with X-ray data. As for the latter data, we combine them with the AKARI mid-IR images to obtain SED maps. Each SED will be compared with model SEDs to investigate the dust size distribution and temperature. From spatial variations of the size distribution, we determine the dynamics of dust, i.e., in-falling to or out-flowing from the center of a galaxy. Finally the results of both studies will be combined to draw a firm conclusion on the origin of dust in elliptical galaxies. The proposed observations have exposure deep enough to detect diffuse emission associated with each galaxy, which are complementary to those so far performed with rather shallow exposure for a larger sample of elliptical galaxies.

LINERs are the most common AGNs in the local universe but their FIR properties are only poorly known. It is believed that most such nuclear emission line regions are situated in hosts with old stellar population and are different from high ionization Seyfert galaxies that show much higher star formation rate (SFR). Recently we found, using Herschel/PACS, that this is not the case in a sample of z=0.3 LINERs that are more luminous than the best studied local LINERs. Many of these sources show L(FIR) as large as 10^11 Lsun and their H-alpha line is extremely week suggesting unusual extinction or a decaying starburst. This proposal suggests a systematic Herschel/PACS study of the most luminous 0.05<z<0.11 LINERs, comparable in their L(AGN) to the z=0.3 LINERs. There are 49 LINERs in this sample and we divided it into two groups according to the distribution of the UV continuum (Galex) light (``nuclear'' and ``extended'' LINERs). We will be able to 1. measure L(IR) of 10^10 Lsun or larger, 2. compare the FIR luminosity with L(H alpha) to derive the extinction properties, 3. check the validity of D4000 as a sSFR indicator, 4. look for the signature of a decaying starburst and, in general, make a detailed analysis of the FIR-based SF properties of this population that are still completely unknown.

This is the second of a two part Herschel project to follow star formation (SF) in intervals of about 700 Myrs, in host galaxies of the most massive black holes (BHs). The first part, which includes 40 AGNs at z=4.8 (t(Universe)=1.2 Gyrs), has been granted time in OT1 and is already providing spectacular results: SFR as high as any observed before, including the most luminous SMGs, and L(SF) way above the prediction of the standard L(AGN)-L(SF) correlation. The present part focuses on the most luminous AGNs at z=2.4 and z=3.5. The z=3.5 group is a flux limited optical sample of the most luminous AGNs. The one at z=2.4 contains 42 BHs with known masses measured by the most reliable Hbeta-based method. The combination of the samples, that are likely to represent three stages in the evolution of the most massive BHs, will allow us to answer several fundamental questions related to the connection between SF and BH activity. 1. What are the relationships between L(AGN) and L(SF) at z=4.8, 3.5 and 2.4? 2. What fraction of the hosts of the most luminous AGNs have already finished, or substantially reduced, their accumulation of stellar mass at every redshift? 3. Can we infer the accumulation of stellar mass through the two periods of about 700 Myrs, and hence the SF duty cycle, assuming these sources will become the most massive galaxies in the local Universe? The z=2.4 sample will be observed with both PACS and SPIRE and the z=3.5 sample only with SPIRE. The total requested Herschel time is 46.4 hours.

One of the biggest challenges in galaxy evolution is to understand how star formation is powered in high-redshift star-forming galaxies. Recent discovery of unusually strong (EW > 500A) Halpha emission in majority of z>4 star-forming galaxies has provided indirect evidence that significant fraction of high-redshift star formation is fueled by mechanisms other than gas-rich merger, suggesting that cold gas accretion is an important source of cold, neutral gas in high-redshift galaxies. FIR cooling lines such as [CII] 158 micron line, produced by the UV stellar radiation like Halpha, afford an efficient probe to study physical properties of the interstellar medium in star-forming galaxies. Therefore, we propose to observe [CII] emission line from local counterparts of high-redshift strong Halpha Emitters to investigate the properties of cold neutral gas in these galaxies and understand how star formation is powered. We request total 11.1 hours of Herschel/PACS observation using Line Spectroscopy AOT for 20 targets, detecting the expected [CII] line with line S/N of >3. Unlike the IR-luminous galaxies or QSOs, HAEs are typical star-forming galaxies at high redshifts thus [CII] observation of local HAEs would provide the first measurement of [CII] and [CII]/FIR ratio of typical high-redshift star-forming galaxies. Thanks to the existing data including spectroscopy, the relationship between the observed [CII] and Halpha, FIR luminosity can be investigated as a function of metallicity, stellar population, extinction, etc. Such relationship would be able to tell whether [CII]/FIR ratio can be used as an indicator that discriminates merger-driven star formation and cold-flow driven star formation. Using the last opportunity of Herschel to access rest-frame FIR cooling lines of local galaxies, this observing program would provide a detailed physical framework for interpretation of future large [CII] surveys in galaxies at higher redshifts using existing or planned submm to radio facilities.

IRAS F00183-7111 is possibly the most luminous ULIRG discovered by IRAS. Nicknamed the 'fire and ice galaxy' since its widely-cited first Spitzer-IRS observations were published in 2004, this galaxy has continued to amaze. Not only does it host the possibly most deeply obscured powerful AGN/quasar in the Local Universe (z<0.4), its extremely wide mid-IR neon line profiles and the extended red wing to the CO(J=1-0) line hint at massive outflows. These outflows may be powered by the radio jets, which appear to be young and which may be responsible for the optically-obscured, highly disturbed ionized neon gas line emission seen with Spitzer, the multiple spatial and kinematic [O III] 5007A components, and the off-nuclear soft X-ray bubble seen by XMM.

So far this luminous z=0.328 merger has remained unobserved by Herschel. Here we propose to study its nuclear outflow at far-infrared wavelengths to reveal optically obscured high-velocity ionized gas outflow components, and to assess the extent and timescale of the neutral and molecular gas outflows, which may drive the evolution of IRAS F00183-7111 from a deeply buried merger remnant to a naked QSO. Our proposed observations may also benefit existing Herschel ULIRG outflow studies by providing measurements for a ULIRG that will extend the current L(AGN) range by a factor of two. This study will further also be relevant for understanding the population of deeply obscured radio galaxies found at high redshifts.

Taking into consideration that dwarf galaxies are by number the dominant population in the current Universe and are considered as the main building blocks for more massive galaxies, studying their origin and evolution allows putting strong constraints on cosmological parameters. Especially, the ISM of metal-poor dwarf galaxies provides an interesting laboratory to study the outcome of stellar feedback and the effect of this metal-enrichment on future star formation. Since dwarfs with a low metal abundance are the best present-day representatives for the conditions in the early Universe, they offer the best opportunity to learn more about the evolution of this galaxy type throughout the history of the Universe. In particular, the proximity of the Local Group enables spatially resolved studies of the lowest surface brightness dwarf galaxies and benefits from a wealth of available ancillary data.

NGC 205, NGC 185 and NGC 147 are three metal-poor dwarf elliptical companions of M31, featuring a ten times less massive gaseous component than predicted from theoretical star fomation models. Either efficient supernova feedback or the presence of a more diffuse ISM component are thought to be responsible for the missing ISM problem.

We propose to probe the ISM through the continuum emission from dust, to better constrain the ISM mass. Recent Herschel observations for NGC 205 confirm the missing ISM problem in this galaxy. We propose to probe the ISM in NGC 185 and NGC 147 with Herschel. With a dust mass detection limit of ~10^2 Msun, SPIRE observations are considered capable of detecting the ISM in NGC147 for the very first time. The unprecedented resolution at PACS wavelengths allows spatially resolved studies of the dust heating mechanisms, dust characteristics (temperature, composition, distribution) and its correlation with the gaseous component, which well shed light on the typical star formation conditions and, in this way, allow a better understanding of their origin and evolution.

We propose to use HIFI, PACS and SPIRE spectroscopy to study the second most luminous HII region in the Local Group: NGC 604. This proposal is a follow-up of the HerM33es OT-KP on M33 which already observed the FIR continuum of NGC 604 at 100, 160, 250, 350, and 500microns. It is also an extension of Galactic observations, particularly high-mass sources of the Water In Star-forming regions with Herschel (WISH) program.

Because of its proximity, high star formation rate, extreme youth, angular extent, and extragalactic location (which removes projection-effect ambiguities), NGC604 offers a unique laboratory for: (1) investigating the density and temperature distribution of the cold gas by modeling the CO ladder; (2) determining the role of dense gas in the star formation efficiency, and (3) provide a link between the Galactic and local low-J studies and high-z, high-J studies through a source that closely resembles a scaled-down starburst.

The detailed study proposed here will enable an in-depth comparison with both Galactic regions of massive star formation (same lines, convolution of Galactic data to same linear scale) and those in nearby galaxies, particularly the LMC. The metallicity of NGC604 is intermediate between that of 30 Dor (the most luminous HII region in the Local Group) and that of the Galaxy. M33, as a chemically young galaxy but well-defined "normal" spiral, provides an important stepping-stone towards the very young irregular systems (i.e. the Magellanic Clouds). In addition to a HIFI CII strip (as in HerM33es), water lines at 557, 752, 9088, and 1097 GHz (latter 3 seen in emission), PACS will cover the entire HII region in the CII[158], OI[63,146], NII[122], NII[205], NIII[57], and OIII[52], while the fully sampled SPIRE spectroscopy will obtain the full CO ladder and CI lines to complement our high-resolution ground-based low-J CO and HI data.

The present study will have long-term legacy value as a unique study of an extremely luminous HII regions mapped at high resolution.

Galaxies grow by accretion of gas in addition to mergers, but the current accretion rate onto a typical spiral is highly uncertain, with values from a few Msun/yr to less than 0.1 Msun/yr. Gas can accrete hot and we observe X-ray emitting gas as well as HI extending several kpc above the plane around some spirals. This may be a hot accretion mode or it may be a galactic fountain, which can be differentiated by metallicity, the fountain having a near-solar value while accreted gas would be 0.1-0.3 solar. Metal absorption lines are detected against a background AGN projected 5 kpc above the disk of the edge-on spiral NGC 891, but due to opacity effects and the unknown depletion factor onto grains, the metallicity is uncertain. Critical metallicity constraints will result from the proposed PACS spectroscopic observations of the C II and OI emission lines in this same region of the halo and in one other region 12 kpc from the disk. These spectra will determine the metallicities of the gas, revealing if the halo region is accreted material, galactic fountain gas, or a combination.

Extensive HI studies of M31 reveal 16 clouds of gas with masses around 3E5 Msun and projected distances of 5-30 kpc. Relative to M31, most clouds have radial velocity differences of 200-300 km/sec, which is interpreted as infall onto the galaxy. Little is know of these clouds, but we are in a position to change that with Herschel spectral observations. Through the proposed PACS C II and O I emission line observations, we can determine the heating of the cloud, its abundances, and its temperature. The abundances inform us of the enrichment of this accretion material, while the temperature, along with the density inferred from the HI data, yields the pressure. These clouds are probably in pressure equilibrium with a hot halo, which is only detectable from X-rays at smaller radii. Therefore the cloud pressure gives us the density of the hot halo and the baryon contribution of this extended hot medium. Finally, we can determine whether the HI clouds are heated through an interaction with the hot halo or only by the photon field of the galaxy.

One of the exciting new results of the Herschel mission is the discovery of massive, high velocity (v ~ 1000 km/sec) molecular outflows in ultraluminous infrared galaxies (ULIRGs). These outflows, powered by stellar processes or by AGN, are so far, best traced by radiatively pumped far-IR OH transitions and are observed in numerous transitions as P-Cygni, absorption, or emission line profiles. Based on our modeling of the lines and continuum, the OH observations imply short gas depletion times, mass loss rates at least several times higher than the star formation rates, and appear strongest in AGN dominated ULIRGs. These mergers of gas-rich galaxies have been caught in the act of dispersing their star-forming molecular fuel as they evolve toward becoming massive, gas-poor ellipticals! Are these outflows driven by radio jets or radiation pressure due to a partially buried AGN or are compact super-starburst winds carving out a view to a previously hidden AGN? We and others have tuned Herschel PACS spectroscopic scans to one or more OH lines in surveys of infrared-bright galaxies to combine with modeling efforts to derive the parameters of these winds. However, in order to help understand the excitation and radiative effects producing these winds and thus to better ascertain the nature of the driving source(s), we propose to fill in the gaps and thus obtain full PACS spectral scans of two key outflow sources: Mrk 231, a broad absorption line (BAL) quasar, and NGC 6240, a close pair of X-ray luminous AGN. The PACS spectral resolution and sensitivity will enable unprecedented understanding of the outflow mass-loss rates, energetics, and the radiative environments to which their ISM is exposed, based on velocity-resolved line profiles of multiple excited level transitions of OH, H2O, CO, OH+, H2O+, and other molecules. A key goal of this program is to provide foundations for the modeling and understanding of the now numerous Herschel OH outflow surveys of ULIRGs.

Recent studies have found that the star formation rate in local Galactic star forming regions is proportional to the amount of dense gas present in the respective regions, once a minimum extinction threshold is surpassed. However, based on the fact that local Galactic star formation represents a relatively small sample of star formation in our own Galaxy and due to the inherent difficulties in obtaining measurements of a larger volume of the Galaxy, the best way to confirm and improve on this result is to observe the star formation rates and the corresponding amounts of dense material over an entire external galaxy. While systematic millimeter-line observations of dense molecular material in an external Galaxy will have to await ALMA, we have started a project to already obtain detailed studies of the infrared luminosities and star formation rates of individual resolved star forming regions in the nearby spiral galaxy NGC 300, using Spitzer, GALEX, APEX, SMA, and ground-based Halpha data. NGC 300 is the most nearby spiral galaxy at southern declinations and thus an ideal ALMA target. We are currently in the process of obtaining total molecular masses of the HII regions in this galaxy from APEX CO observations while constraining the star formation rates with Spitzer, GALEX,and Halpha data. Here we propose to obtain unbiased mapping of the entire galaxy in both the PACS and the SPIRE far-infrared and submillimeter bands. This will provide a) an unbiased way to find and identify giant molecular clouds in this galaxy and obtain their masses, b) much better spectral energy distributions of the HII and other star forming regions and c) improved star formation rates for these regions.

One of Herschel's most important legacies will be the detection and systematic study of large-scale molecular outflows. Galaxy outflows are a key ingredient in galaxy evolution: they regulate the growth of galaxies reducing the amount of molecular gas available for star formation, contribute to establish the observed correlation between the black hole mass of a galaxy and the stellar velocity dispersion of its bulge, and play a critical role in the morphological transformation of gas-rich mergers into ellipticals. Before the launch of Herschel, our knowledge of the properties of galactic outflows was mostly limited to the study of the ionized and neutral atomic gas. Little was known about the amount of molecular gas involved in the outflows, its velocity structure and spatial distribution. Herschel revolutionized this field. Since 2009 our group has discovered powerful molecular outflows in the majority of the ultraluminous infrared galaxies (ULIRG) studied. These outflows can be easily identified in the form of strong blue-shifted absorption and red-shifted emission P-Cygni profiles in the OH 119, 79 and 65micron lines. The outflows in some of these galaxies have maximum velocities >1000km/s, mass outflow rates several times larger than the SFR in the galaxy, and molecular gas depletion times <10Myr. Objects with higher AGN luminosity appear to have higher terminal outflow velocities and shorter gas depletion timescales, which indicates that the molecular outflows in these systems might be mostly driven by the AGN. Here we propose to complement current Herschel molecular outflow studies observing a sample of 10 ULIRGs selected among the most IR luminous objects in the local Universe. We will use the redshifted OH 119micron doublet for this purpose. These observations will extend to higher SFR and AGN luminosities the outflow trends found in our previous studies and will be an excellent comparison sample for future ALMA high-redshift observations of the same line in objects with similar IR luminosities.

Studies of evolved systems like AM0644-741 and Cartwheel find the ISM in the starburst rings to be overwhelmingly atomic despite conditions (e.g., pressure and ambient far-UV fields) clearly favoring a dominant molecular component. Moreover, the local molecular fraction anti-correlates with SFR/area, yielding unusually high star formation efficiencies (SFE) and a highly peculiar star formation law. AM0644-741's starburst ring moreover appears mostly stable gravitationally (Q = 2-6). We have argued that these all follow naturally from the ISM's >100 Myr confinement time in the ring, which amplifies the destructive effects of embedded OB stars and SNe, producing an ``over-cooked'' ISM, i.e., one characterized by small H2 clouds, and a large photo-dissociated HI background. Due to reduced dust columns, H2 is poorly traced by CO rotational lines, and we expect a large ``dark'' molecular component in the ring. We will use PACS and SPIRE photometry with existing IRAC and MIPS data to (1) construct infrared-submillimeter SEDs for the rings of AM0644-741 and Cartwheel to determine the total mass and distribution of H2 by its dust emission following Israel (1996) and Leroy et al. (2009), (2) re-evaluate their peculiar SFE, non-Schmidt star formation laws, and gravitational stability. Not finding a large hidden H2 component would imply that star formation is triggered by other processes (e.g., collisions) at unusually high SFE.

We propose to use HIFI to observe a complete set of molecular ions related to the PDR-XDR-CRs chemistry toward seven galaxies covering all types of activities. We have selected the hydrides CH+, CH, OH, H2O+, HCl, OH+ and H3O+, and the high density tracers HCN, HCO+ and HNC suggested to be affected by X-ray and shock induced chemistry. To cover a wide range of nuclear activity we will observe three ULIRGs, Arp 220 (cold), NGC4418 (warm) and Mrk231, one LIRG, Arp 299A, the AGN NGC1068, and two starbursts, M82 and M83. The high spectral resolution provided by HIFI will be fundamental to disentangle the complex line profiles (usually P Cygni) often observed in galaxies due to clouds observed along the line of sight with different velocities and large changes in the molecular abundances ratios. The H2O, OH+, H2O+ and H3O+ abundances and abundance ratios will be used to disentangle the CR/Xray and the PDR components in the galaxies.

Long-duration gamma-ray bursts (GRBs) have been found to be associated with violent and luminous supernovae. Such massive stars have very short lifetimes and therefore GRBs pinpoint the location of galaxies that have recently undergone an episode of star-formation. Hence, GRBs may provide a promising means of identifying and studying star formation in the Universe. Here we propose to critically assess this issue using the determination of the gas excitation state for the closest GRB host galaxy. This is crucial because GRBs are potentially excellent tracers of the global star formation history, which is of fundamental importance to our understanding of galaxy formation. However, this kind of study requires prior detailed investigation of GRB host galaxies, which has not been fully addressed yet. GRB 980425 associated with SN 1998bw is the closest known GRB (redshift z=0.0085), therefore it is an excellent laboratory for detailed GRB studies. The interplay between dust thermal emission, radio emission and star-formation is not yet well understood even in the closest known GRB host. Moreover, the properties of molecular gas are very poorly understood for GRB hosts, since none of them was detected spectroscopically in the far-IR. Herschel will provide an important step forward with both of these issues. Here we propose a detailed study of the closest known GRB host. From the CO, CII and OI lines of the host of GRB 980425 we will determine its ionisation state. This will lead to an understanding of whether the GRB 980425 host can be regarded as a normal star-forming galaxy, or its star formation rate is enhanced. This will have consequences for interpretation of GRBs as tracers of star formation in the Universe.

Understanding the processes governing the formation of clouds and stars in merging systems is key for the study of how galaxies evolved in the early Universe. The 30 Doradus region in the low-metallicity Large Magellanic Cloud (LMC) is the nearest example of this process, resulting from the interaction between the LMC and the halo of the Milky Way. This makes 30 Doradus the prime laboratory to study these large-scale dynamical processes under conditions that are similar to those at early cosmological times. We propose to use Herschel to obtain a large-scale uniform sampling of this region in [CII] 158um, [NII] 122um and 205um, and [OI] 63um and 146um lines with PACS, and at selected positions in [CII] with HIFI. With this data we will derive the large-scale distribution of the density and pressure of the low-metallicity gas revealing the characteristic signatures of shocked gas. This will then be used to determine the relationships among the diffuse, "dark H2", and dense molecular gas in the 30 Doradus region. We will also derive the electron density distribution of the gas and from this the contribution from ionized gas to the observed [CII] emission. The proposed observations will allow us to study the effect of large-scale gas compression in the multiphase, low-metallicity interstellar medium of 30 Doradus. This information will be valuable for the interpretation of future observations of [CII] in high-redshift galaxies made with ALMA

Recent Herschel observations have detected up to 0.7 Msun of cold dust surrounding SN 1987A . This discovery implies that supernovae could be responsible for the large dust masses detected in high red-shift galaxies and opens opportunities in the Herschel era for detecting and measuring accurate cold dust masses in extra-galactic supernovae. One data point from SN1987A is insufficient to resolve the fundamental question of the origin of dust in early Universe, therefore we propose Herschel PACS and SPIRE imaging observations of the two nearby supernovae SN 2004et and SN 2004dj. After SN 1987A, they are the closest well-known supernovae with evidence of dust formation from Spitzer and other ground-based observations. Our scientific goals are i) to detect far-infrared and submm emission from supernovae, ii) to understand the spectral energy distribution of the SNe for temperatures and dust composition, and iii) to estimate freshly formed dust mass. These added observations are essential to help determine if supernove are significant dust makers in the early Universe.

At present, though we suspect that highly obscured AGN may play a major role in the infrared background and the evolution of galaxies, we have a poor empirical measure of the intrinsic spectral energy distributions of dust-obscured AGN. It is presumed that the obscured X-ray and UV photons are re-emitted in the infrared, but with what SED shape? How important is very hot dust versus very cool dust? What does the SED say about the circumnuclear structure, compared to unobscured AGN? To address these questions, we propose PACS/SPIRE 60-500 micron imaging of five nearby Compton-thick AGN, which we will combine with an additional four targets already in the Herschel archive. We will combine this dataset with our existing dataset from Spitzer to create high--quality 5--500 micron SEDs. This will help us understand how AGN obscuration works in the nearby universe, and will provide templates to apply to higher redshift to better understand the cosmological importance of buried accretion and its contribution to the infrared and X-ray backgrounds.

To explain the nature of galaxies in the present day universe, contemporary models of galaxy evolution require feedback to expel a substantial fraction of the gas and dust fueling stellar and black hole growth, thereby driving galaxies into quiescence. Post-starburst galaxies are systems found precisely in this phase -- after star formation has been abruptly halted. Due primarily to lack of sample and sensitivity, however, the dust and gas content of post-starbursts has remained essentially an unknown. Until recently very challenging to find and study, large samples of close to one thousand post-starbursts can now be selected using the combined power of SDSS and GALEX.

We propose targeted follow-up of a sample of 33 post-starbursts, carefully selected to sample uniformly a wide range of precisely determined post-burst ages, from 50Myr to 1.5Gyr. To construct this sample, we have powerfully extended our unique UV/Optical selection using pre-release WISE full-sky photometry, which provides critical sampling of their mid-infrared SEDs. With PACS and SPIRE photometry extending SED coverage beyond the dust emission peak, and PACS spectroscopy in the dominant gas cooling lines [CII] and [OI], we can begin to address the question of how and why galaxies stop forming stars and fade into quiescence.

Herschel alone can provide the vital, unique information on the conditions and content of neutral gas and dust in galaxies during this crucial transitional phase in their evolution. Our program will 1) characterize the ISM content in these systems as a function of post-burst age, 2) search for clues identify their quenching mechanisms, 3) explore the form and behavior of dust in unique and extreme environments, and 4) test the laws governing star formation and the flow of energy through the ISM in a wholly new regime -- where gas and dust are plentiful, but where star-formation has recently and abruptly ceased.

We propose to measure the far-infrared (FIR) [O III] transitions in several extragalactic HII regions with the goal of understanding the proper calibration of gas phase oxygen abundances. Despite being a key attribute that influences galaxy evolution, the absolute scale of nebular abundances are highly uncertain (0.7 dex). This uncertainty is rooted in the limitations of optical emission lines that are strongly affected by temperature variations and extinction. With Herschel we have the ability to solve this long standing calibration uncertainty. To this end we propose observations of HII regions in nearby galaxies that will complement Herschel [O III] observations by Herschel Open Time Key Projects and allow complete coverage of the range of metallicities present in the local universe. High quality optical spectra already exist for all of the targets we propose. Thus, we have an unprecedented opportunity to finally calibrate the chemical abundance scale across several decades of metallicity using the PACS spectrometer on-board Herschel. The FIR is a critical wavelength regime that has never been visible with the resolution possible to begin matching measurements with long-slit optical observations. This is a unique opportunity to constrain chemical evolution models and the enrichment history of the local universe.

Feedback mechanisms, i.e., jets, winds, and radiation pressure from active galactic nuclei (AGN) are thought capable of suppressing or triggering star formation in their host galaxies. Their past occurrence might have even affected the observed luminosity functions of present-day galaxies. AGN feedback signatures have been mainly sought for in OH, OH+, H2O, and H20+ absorption line profiles with Herschel. Similar queries with the high-J CO emission lines have not been performed even though they are feasible. We propose to look for feedback effects in high-J CO lines in 6 local AGN that are unique for this purpose. They have highly turbulent motions of warm H2 gas, as seen with Spitzer (Dasyra & Combes 2011). Their H2 lines are both very broad and strong, with typical velocity dispersions of 200-300km/s and M_H2/LIR ratios 5-160 times higher than that of Mrk231. In 4C12.50, the H2 line wings indicate the presence of a massive (5*10^7M_sun) outflow. If the strong H2 emission originates from gas shocked by AGN feedback mechanisms, it can be associated with strong high-J CO emission. Our sources allow for a direct comparison not done before: that of the gas velocity dispersion as probed by the two most abundant molecules, H2 and CO, in the T range where this becomes possible. We will also: (i) compare the widths of high and low J CO lines, (ii) locate the emission peak of the warm gas, (iii) model its excitation mechanism, and (iv) query for outflow-related line wings. Upon success, we will compute the warm gas mass (fraction) that the outflow entrains. The flow rate will be compared with the star-formation rate to indicate if the outflow is AGN driven, and if it can quench star formation. To achieve our goals we propose to observe with PACS the CO (15-14) and (18-17) lines in all 6 AGN, complementing them with PACS data of the [CII], [OI] 63 and 146 micron lines, and SPIRE spectra, when not available. The time investment for this basic experiment is modest, 11.6 hours with PACS and 5.8 hours with SPIRE.

We propose to map emission from cold (<30 K), newly-formed dust in the ejecta of the core-collapse supernova remnant 1E 0102.2-7219 (E 0102) using Herschel PACS observations. E 0102 is a key object for understanding supernova dust production: it is one of few remnants where we have clear evidence of dust formation from mid-IR observations of ~10^-3 solar masses of hot dust in the reverse shocked ejecta. A large fraction of the newly-formed dust, however, may be located in the central, unshocked ejecta and its cold temperatures have kept it hidden at mid-IR wavelengths thus far. Observations with PACS at 70, 100 and 160 microns have the sensitivity and angular resolution to measure the mass of dust in the unshocked ejecta of E 0102 for the first time. With the observations proposed here, we will either discover a reservoir of cold dust in E 0102 or provide a direct counter-example to recent theoretical and observational studies that suggest supernovae are important sources of ISM dust.

We propose deep [CII] mapping of atomic-gas dominated regions in several nearby galaxies. These regions represent interstellar medium conditions that have not yet been explored with Herschel or any other facility and will remain unexplored in the foreseeable future if they are not observed with Herschel in OT2. We will use the proposed [CII] observations to measure the ISM heating rate and constrain the heat source in regions where the photoelectric effect driven by ultraviolet photons from young stars does not dominate. These observations are crucial for characterizing the low surface brightness [CII] emission, which is potentially an important contributor to the total [CII] emission from galaxies.

We propose to observe 40 low-inclination, late-type spiral galaxies from our DiskMass Survey in all six Herschel PACS+SPIRE bands, requiring an allocation of 40.8 hours. The powerful combination of these Herschel data and our existing DiskMass data will allow us to calculate spatially resolved dust-mass and dust-temperature maps using both traditional SED fitting and more advanced radiative transfer modeling through a clumpy (fractal) medium. We will also be able to estimate bolometric corrections to dynamically measured stellar mass-to-light ratios made in the UV and optical; this will provide an unprecedented calibration of stellar-population-synthesis modeling at these wavelengths, which is important for applications at intermediate and high redshift. Finally, we will provide a novel comparison of spatially resolved dust properties with direct measurements of the stellar, atomic-gas, and dark-matter mass densities. We emphasize that, unlike other Herschel Key and GT programs, we use stellar kinematic data (collected over six years using 4m-class optical telescopes) to directly measure the mass surface density of each galaxy disk. Using these measurements of the disk potential and the proposed Herschel observations, our sample will be uniquely qualified to describe the detailed pressure balance in the interstellar medium and its correlation with the measured dust properties, as well as their empirical links to star formation and disk stability. These topics address our core understanding of the evolution and self-regulation of galaxy disks.

Luminous Infrared Galaxies (LIRGs; having LIR > 10^11 Lsun), emit a significant fraction of their bolometric luminosity in the far-infrared and are a mixture of single galaxies, interacting systems and mergers, exhibiting enhanced star formation rates and a higher fraction of Active Galactic Nuclei (AGN) compared to less luminous galaxies. With the Great Observatories All-sky LIRG Survey (GOALS), we are measuring the properties of a large, complete sample of 202 low-redshift LIRGs across the electromagnetic spectrum using Herschel, Spitzer, HST, Chandra, GALEX and a suite of ground-based observatories. As part of an accepted OT1 proposal, we are targeting the entire GOALS sample in the [CII] 157.7 and [OI] 63.2 micron emission lines and the OH 79 micron absorption feature, along with half the sample in the [OIII] 88 micron emission line. Here, we propose to complete our [OIII] emission line survey, and observe the brightest GOALS sources in the important [NII] 122 micron line with PACS. We will target 123 galaxies in [OIII] and 122 galaxies in [NII] line for a total requested time of 69.8 hrs. The PACS data will allow us to penetrate the dust and measure the spatial distribution, dynamics and overall energy budgets in a large sample of LIRGs at low redshift for the first time. In addition to providing a measure of the physical conditions in the warm, neutral and ionized ISM in LIRGs, the complete dataset will allow us to establish a precise, quantitative FIR-based measure of the star formation rate that can be used across a wide range of galactic luminosities, even in the presence of powerful AGN. GOALS, with its rich ancillary dataset that covers X-ray through millimeter wavelengths, provides the perfect sample for this study. Our proposed Herschel/PACS observations will greatly extend the work started with ISO, and lay the foundation for high-redshift extra-galactic studies with future facilities that will target the FIR and sub-mm spectral regions over the next decade.

The coevolution of central black holes and their host galaxies appears to be driven by starburst and AGN activity, and their respective energy feedback. Depending on the evolutionary state of the system, the AGN can be heavily obscured and appear as a Type 2 source. The relationship between the AGN and the galaxy has been extensively investigated by focusing on the stellar component of the host, especially the velocity dispersion and luminosity of the bulge, which empirically are closely coupled to the black hole mass. However, an insufficient amount of attention has been devoted to characterizing the ISM of the host galaxy. Here we propose to obtain FIR photometry with PACS and SPIRE for a volume-limited sample of Type 2 QSOs, complementary in redshift and luminosity to a sample of z < 0.5 Type 1 QSOs being studied by our team in OT1. Our goal is to derive robust dust masses and temperatures, and star formation rates for these two classes of QSOs, to test their physical connection. If, as has been suggested, Type 2 QSOs are the progenitors of Type 1 sources, we expect the Type 2s to be more gas (dust) rich, and perhaps have higher star formation rates, than the Type 1s. For objects at the mean redshift of z = 0.2, we can constrain the mass of warm (~60 K) and cold (~25 K) dust down to 3E+5 and 3E+7 solar masses, respectively, similar to levels found in the Milky Way. These data will provide a fundamental dataset for testing the evolutionary link between Type 1 and Type 2 QSOs, and the broader relationship between black hole growth and galaxy formation. The goals of this proposal mesh well with one of Herschel's main mission statements: "Unveiling hidden details of star and galaxy formation and evolution."

We propose to use Herschel/PACS+SPIRE to study dusty extreme star formation (SF) in a unique carefully-selected sample of 23 nearby low-metallicity dusty blue compact dwarf (BCD) galaxies in the local universe. Like extreme starbursts, and unlike most BCDs and other dwarf galaxies, their SF occurs in compact, dense regions with high star-formation rate (SFR) surface density. They are the best local analogs to study how stars form at high redshift, and complement the vast majority of more quiescent BCDs already observed by Herschel. Our BCD sample is unique among dwarf samples in that it has been constructed by choosing objects from the Sloan Survey with large MIR IRAS fluxes, similar to the 2 active BCDs that have been recently discovered by WISE through their very red WISE colors. It also has all the ancillary optical, near-infrared, and Spitzer data, necessary for a detailed interpretation of the Herschel data. With PACS+SPIRE photometry, we will fit the spectral energy distributions (SEDs) constrain the mass of the cool dust component -- hence better estimate the total dust mass -- and compare it with the stellar and gas masses. We will also look for trends in SED shape with compactness and SFR. By combining the data on active BCDs with that on passive BCDs in the Spitzer and Herschel archives, we will be able to compare SEDs and modes of SF over a wide range of SFRs, metallicities, and dust properties. Ultimately, these extreme BCD starbursts may provide local templates to compare with the dusty galaxies in the high-z universe.

PACS observations of the [CII] 158 micron emission line are proposed for 56 luminous, dusty galaxies to determine if there are starbursts so obscured by dust that the starbursts are weak or invisible in the mid-infrared PAH features observed with the Spitzer Infrared Spectrograph (IRS). Are there LIRGs and ULIRGs classified as AGN which really are heavily obscured starbursts? Because of the much smaller extinction affecting the [CII] feature, large f([CII])/f(PAH) ratios would show the presence of such obscured starbursts. Sources proposed include 18 "pure" starbursts to improve the f([CII])/f(PAH) calibration for these, 32 sources classified as AGN/starburst composites, and 6 sources with weak PAH and very strong silicate absorption. This proposal builds on the success of our OT1 program for which a summary is given of the excellent [CII] detections so far obtained and analyzed for a variety of luminous sources with IRS starburst/AGN classifications.

We request a total of 5.3 hours of Herschel PACS and SPIRE time to investigate the physical nature of an extraordinarily far-IR bright system discovered by the WISE data. This object was first selected to have an extremely red mid-IR SED, very bright at 22micron (38mJy) and not detected at WISE 3.4 and 4.5 micron. At the WISE 12micron position, we found it has IRAS far-IR emission, (600+-59)mJy & (855+-170)mJy at 60 and 100 micron respectively (2' beam). A small 350 micron map, taken with the CSO SHARCII under an exceptionally good weather condition, has detected a 32mJy source at the WISE position. The large discrepancy between fluxes at IRAS 100 micron and CSO 350 micron is intriguing. We propose to clarify the nature of this system --- whether a single or a group of far-IR bright sources --- by utilizing Herschel's high spatial resolution and fast mapping speed. The Herschel photometry, together with the Keck spectra, will allow us to determine the full IR SEDs and the physical parameters such as IR luminositie, SFR and star formation efficiecy.

In addition, the deep Keck LRIS spectrum of the galaxy closest to the WISE 12 micron position has found an emission line object at redshift of 0.593, and the Keck NIRC2 K-band Adaptive Optics image shows an extended, disk like galaxy. At z=0.593, the strong IRAS far-IR emission implies very high L(FIR), in the range of (2.1-10)e+12Lsun, with the lower limit set by considering only 1/4 of the IRAS fluxes. We propose to obtain SPIRE FTS spectroscopy to measure [CII]158um line. At this redshift, this line can only be observed by Herschel, and is outside the ALMA wavelength window. With the measured [CII]-to-L(FIR) ratio, we can constraint the molecular gas mass of Source A by utilizing the correlation between [CII]-to-L(FIR) and L(FIR)/M(H2). Even with null detection, our observation will provide meaningful constraint on the ISM properties of this ULIRG.

Combining WISE and Sloan Digital Sky Survey (SDSS), we have identified a sample of 9 QSOs with flux(22um)>100mJy and with spectroscopic z~0.1−0.2 for Herscel PACS spectroscopy. Our targets are so bright at 22 micron, even without far-IR observations, their predicted fluxes at 100 micron would exceed 300 mJy based on the type-I QSO SED which has the minimum far-IR emission. For this bright QSO sample, we request a total of 23.8 hours to measure far−IR fine structure lines with PACS spectrometer. The extremely bright IR fluxes and the narrow redshift slice allow us to simultaneously observe the two brightest far−IR lines, [OI]63um and [CII]158um. We can therefore estimate the line ratios, in combination with Photo−Dissociation Region (PDR) models, to provide physical characterization, including gas temperature, density and intensity of UV radiation field, of the warm interstellar medium (ISM) in these luminous objects. The proposed observations will allow us to determine [CII] line and far-IR continuum luminosities. With the [CII]-to-L(FIR) alone, we can already estimate L(FIR)/M(H2) ratio utilizing the published correlation by Gracia-Carpio et al. 2011, thus allowing estimates of molecular gas masses. The far−IR continuum estimates, with the four mid−IR photometry from WISE, can determine if the total IR luminosities could be produced by starbursts, and if so, give estimates of star formation rates. One additional advantage of this sample is that their high SNR SDSS spectra can be used to calculate black hole masses based on fairly reliable low ionization lines. The calculation will allow us to investigat e any relation between black hole properties, including mass and accretion rate, and the gas medium probed by the far−IR data. These proposed spectra will contribute to building up a Herschel legacy with far−IR spectroscopy dataset which will extend beyond ALMA and JWST.

We propose to carry out PACS and SPIRE mapping of the dust continuum emission from the nearby, low metallicity dwarf galaxy IC1613. The maps will have spatial resolutions of 24 pc to 120 pc, allowing us to probe dust temperatures, formation and destruction processes on the scale of individual star-forming clouds. The results will also be combined with our extensive ancillary datasets to search for evidence of molecular hydrogen. IC1613 fills an important niche in the archive, as Herschel's resolution and sensitivity enable us to push these kinds of studies to lower metallicities and lower star formation rates than have previously been accessible.

The nuclear spiral in M31, consisting of ionized and neutral dusty gas clouds, shows optical emission lines characteristic of LINERs. Yet the lack of UV radiation from either an active nucleus or massive young stars makes the ionizing source of this nearest LINER a longstanding puzzle. We propose a PACS spectroscopic mapping of several fine structure lines, including [C II], [O I] and [O III],from the nuclear spiral. We will derive for the first time the spatial distribution and kinematics of the circumnuclear neutral gas in M31, with an unparalleled linear resolution of 40 parsec for a massive external galaxy. These FIR lines, together with the optical and mid-IR emission lines mapped by HST and Spitzer observations, will enable us to assess the importance of various ionization/excitation mechanisms. Specifically, we will test the cosmic-ray heating scenario, which is favored by energetics considerations for the nuclear spiral. This study will advance our understanding of the physical regulation of galactic circumnuclear environments, which is in turn crucial to understanding the evolution of super-massive black holes and their host galaxies.

We propose PACS+SPIRE observations from 70 to 500 micron of the giant (180 kpc across), massive (~5.5 10^10 Msun of HI), strongly star-forming collisional ring around NGC5291, a unique gas-rich object in the nearby Universe. These observations, in combination with available data and models, will allow us to not only study star formation and the dust properties in an unusual and extreme environment, but also to get insight into the nature of Dark Matter. Indeed our team showed that the gravitationally bound objects formed within the ring of NGC5291 contain an unexpected dark component. It is thought that this matter should be baryonic as the material in the collisional ring comes from galactic disks. The most likely candidate is H_2 that is not properly traced by CO. Herschel will allow us to trace this unseen component through dust emission and constrain its nature. The method requires to characterize the dust properties and estimate the dust/gas mass ratio, which are not known in collisional rings and might differ from those in other environments. Indeed, collisional rings are created by high speed collisions. The strong shocks generated by the impact have likely affected the dust properties. Through state-of-the-art modeling of the SED from the UV to the radio, we will constrain the properties of the dust such as their temperature, the distribution of the grain sizes, etc. Addressing the question of dust processing in high-speed collisions is fundamental to derive the molecular gas mass. Finally having an accurate estimate of the total molecular mass, we will be able to address star formation laws, in particular the Schmidt-Kennicutt relation which is suspected not to be universal. This will allow us to determine whether it varies with the environment, having selected an "extreme" one, such as the collisional ring of NGC5291. The project will require the combination of already available VLA HI observations, star formation tracers and Herschel PACS+SPIRE photometry.

We request 9.9 hours of observing time to map M33 at 70 micron. This project will enable a spatially-resolved investigation of HII regions in this galaxy, with the goal of determining changes 1) in the respective amount of PAH, stochastic and equilibrium dust emissions, in order to 2) constrain the radiation field and the properties of dust emission as a function of the evolutionary phase of the HII regions and across the disk of the galaxy. We will resolve the internal structure and physical properties of the HII regions down to ~24 pc (<6"), and construct spatially-resolved, pixel-based, UV-to-FIR SEDs. This proposal is a key complement to the HerM33es key project which mainly focuses on the mapping of major FIR cooling lines, with only a small fraction of the time dedicated to imaging from 100 micron to 500 micron (PACS and SPIRE).

In observational studies of the high-redshift universe, the potential of the HI Lyman-alpha (Lya) to answer open cosmological questions is well established. This potential, however, is hampered by the fact that Lya is a resonant line, scatters in HI, and undergoes a complicated radiative transport. It has recently been suggested that certain structural geometries of the multiphase ISM could be even more important than the overall dust content in regulating the Lya visibility. The simplest scenario to unify the requirements for Lya with what we know about the phases of the ISM in galaxies is that these scattering surfaces must be the typical photodissociation regions (PDR), surrounding dusty molecular clouds within.

Currently there is no observational test of this theory. We propose here to obtain unresolved PACS spectroscopy of the [C II] and [O I] lines, and photometric observations in all three channels, of 10 galaxies in the local LARS (Lyman Alpha Reference Sample) sample. These data will allow us to 1) Measure the total mass of PDR gas and contrast it against the total HI mass (already obtained). We will test the hypothesis that when more of the HI is condensed around high-density clumps, the ISM is more conducive to the transmission of Lya photons. 2) We will use the [O I]/[C II] ratio and the total ratio of ([O I]+[C II])/FIR in conjunction with PDR modelling, to constrain the HI density in PDRs. 3) From the PACS photometric points we will model the IR SED, compute dust masses, gas-to-dust ratios, attenuation from UV/FIR, and contrast them all against Lya properties.

We propose to obtain the PACS and SPIRE scan maps of a sample of 34 exceptionally gas-rich galaxies extracted from the ALFALFA extragalactic HI survey. These very HIgh HI mass (HIghMass) galaxies have HI masses > 10^10 Msun and are also very gas-rich for their stellar masses; 17/34 have M_HI>M_star. Are they in an arrested stage of evolution or do their huge HI disks, evident in our HI synthesis maps, result from recent baryon accretion? In combination with the HI synthesis maps (EVLA, GMRT, WSRT), GALEX UV, Halpha, optical broadband and CO studies, FIR/submm maps will cover a critical wavelength range of the dust emission spectral energy distribution and will allow us to determine the dust masses, temperatures and grain size distributions so that we can explore the interplay between the dust, stellar, gas and dark matter components within each galaxy and identify the dust variation trends within the HIghMass sample. In particular, Herschel observations will help us to (1) explore the unique dust behavior in the HIghMass galaxies and map the extent of the cold dust disk; (2) test the origin and evolutionary stage of them and infer molecular masses via the dust to gas ratio; (3) probe the dust-obscured star formation and study the dust heating mechanisms in their extended massive HI disks. Identified first as a class only by ALFALFA, the HIghMass galaxies represent the local counterparts of the populations which are likely to dominate future studies of HI at higher redshift with the Square Kilometer Array.

We have now reached a relatively mature understanding of the physical processes that regulate the ISM in galaxies, but we are woefully ignorant of the details of the cycles between gas in and outside of galaxies. This is unfortunate because understanding the gas physics in a wide variety of environments is the key to determining the relevance of the physical mechanisms that have been invoked for driving galaxy evolution -- from the feeding of star formation through accretion of cold gas to the regulation of star formation through the mechanical energy ejected by massive stars and AGN. To help to overcome our ignorance about the nature of star formation in different environments, in this case in galaxy halos, we propose to use PACS to observe [CII] in many selected regions of the "bridges" of HI in the nearby group of M81 and in the Magellanic stream, two of the nearest intergalactic gas flows. These regions are excellent targets for this type of study because it has a wide range of HI column densities and stars have recently formed in the gas flow between its galaxies. In response to the comments of the OT1 panel, the Magellanic stream was added as a foil to the M81 group in that it has scant evidence for recent star formation. [CII] is the main coolant and an excellent tracer of the cold neutral medium in galaxies. By combining these data with dust maps from Spitzer, Herschel, HI and H-alpha observations, we will investigate the mass balance between the warm and cold neutral medium to constrain the role of turbulence in regulating this balance, which is key to the cooling and fragmentation of gas and to regulating star formation. Investigating the nature of star formation in a halo of a galaxy or group is one of the critical first steps in understanding what occurs during the cosmological accretion of gas and thus help determine what processes drive the evolution of the ensemble of galaxies.

Long gamma-ray bursts (LGRBs), are the brightest transient events in the Universe. This, combined with their wide range in redshift and the fact that they are associated with the collapse of massive, low metallicity stars, establishes LGRBs as powerful probes of star formation and an unbiased method for identifying high redshift galaxies. Targeted observations of LGRB hosts have shown them to be typically blue, low metallicity, dwarf to intermediate mass galaxies. However, the role of dust in the star formation history, chemical enrichment and evolution of these sources is currently still unclear, yet its importance cannot be overstated as it is directly related to the origin of the LGRB. The dust properties of LGRB host galaxies can be uniquely investigated with Herschel due to its ability to probe the peak of the dust emission, particularly in the nearby Universe where we can gain a fundamental understanding of the role of dust in these systems. In this proposal we request 48 min of Herschel (PACS and SPIRE) observations of 2 local z≤0.1 LGRB host galaxies, already well studied over a large part of the electromagnetic spectrum. Our proposed targets are the only Herschel-detectable LGRBs hosts in the local Universe which have properties resembling those of the general LGRB population, setting our study key in understanding the processes and interstellar medium (ISM) conditions associated with LGRBs. Our proposed observations will enable us to examine in detail currently unconstrained properties, such as the dust mass, dust temperature, dust to gas ratio, star-formation history and extinction. In addition, for the first time, we will be able to link the LGRB explosion to the conditions and chemical evolution of the ISM as as well as examine the role of dust in LGRB hosts harbouring metal poor, massive stars.

The discovery of molecular outflows from AGN and starburst galaxies has been a major success of the Herschel Space Observatory and moved AGN feedback into the focus of Herschel science. However, feedback is more than winds, and observations of winds alone will only provide a limited picture of how AGN regulate star formation in galaxies. Recent observations suggest that gas-rich AGN host galaxies can have very low star-formation rates, up to 60 times less than expected for their gas surface densities. Why are these galaxies not forming stars? One possibility is that the injection of mechanical energy through the AGN is making the gas too turbulent to become gravitationally bound, to collapse and to form stars. Thus, star formation in AGN host galaxies may be regulated by fundamentally similar mechanisms as star formation in molecular clouds in the Milky Way and other 'ordinary' galaxies.

Here we propose to measure [CII]158 with PACS in 6 nearby galaxies with radio nuclei to test this hypothesis. We focus on galaxies with radio nuclei without strong star formation or quasar emission, because we wish to study the consequences of the rapid injection of mechanical energy through the AGN into the ISM. Radio-dominated AGN provide the cleanest environment for such a study because their UV radiation is faint, and we expect the shock contribution to dominate over that of UV heated star forming gas. However, many of our results can be cautiously extended to all types of mechanical interactions between AGN and gas. We will compare the [CII] line fluxes with those of warm H2 in the Spitzer archive. For highly turbulent gas that is not gravitationally bound, we expect the gas not to be well shielded, resulting in high [CII]/H2 ratios of 1-5. For the same reason, [CII] could also be an interesting tracer of low surface-brightness emission from winds. NIR imaging spectroscopy will serve as a benchmark to separate systemic line emission from putative wind components and to measure turbulent velocities in the CNM.

Quasar feedback has become a major ingredient in galaxy formation models, invoked to explain the absence of overly massive galaxies, the hot intracluster medium and the black hole / host galaxy correlations. Using ground-based spectroscopic observations, we have discovered high-velocity ionized gas outflows from luminous obscured quasars, which could be the long-sought ``smoking-gun" signature of quasar feedback. We propose deep photometric observations with Herschel to determine the far-infrared spectral energy distribution of these objects. We will use these data to confirm that the observed outflows are driven by the supermassive black hole activity rather than by star formation in the host galaxy. Furthermore, we will quantify the relation between the kinetic energy of the outflow and the radiative power of the quasar. Herschel observations are the only avenue to establish the driving mechanism and energetics of quasar feedback.

We propose to study the far-IR/submm emission (both sources and diffuse) of two southern regions around declination -50 and -57 degrees which have been and will be surveyed by the Cosmic Microwave Background (CMB) experiments Background Imaging of Cosmic Extragalactic Polarization (BICEP and BICEP2) (Chiang et al., 2010) and `E and B Experiment' (EBEX) (Reichborn-Kjennerud et al., 2010). Our goal is to measure and characterize the Galactic diffuse and point source emissions which represent the main contaminants to the CMB in the frequency range covered by Herschel, which is complementary to the one of the above CMB experiments, "directly in the area which will be covered by those experiments". These measurements will bring invaluable information to control the foreground emissions in those experiments, therefore contributing to gain insight into most important cosmological processes related to the CMB anisotropies, which compete with the diffuse Galactic and extra-Galactic point source emissions.

Compact groups of galaxies represent density enhancements in the Universe comparable with clusters and are dominated by early type galaxies that lie in the "Green Valley" between the blue and red sequence. Our observations of a sample of such groups has revealed that 10 percent of our targeted group members show unusually powerful mid-IR H2 emission lines relative to PAH emission--suggesting shock-excitation. Most of these galaxies lie in the optical green valley, and exhibit specific star formation rates that lie between spirals and elliptical suggesting that they are a transition population in which shocks may play a role in their color evolution.

We propose to map key far-IR cooling lines [OI], [CII] and CO with the PACS and SPIRE spectrometers to both map and quantify the strength and distribution of shocks to search for clues about how they might be affected by their environment. We will also use PACS and SPIRE imaging to constrain dust SEDs to estimate SFRs and dust/gas masses to explore whether the shocks may heat the gas above the threshold for star formation--hence shutting down new star formation. Alternatively, by comparison with VLA HI maps which show considerable tidal material in the groups, we will search for evidence that accretion from tidal streams is responsible for re-igniting new star formation-thus modifying their optical colors. This proposal will, for the first time, test whether shocks may play a transformative role in galaxy evolution.

NASA's Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at 3.4, 4.6, 12 and 22 microns (W1, W2, W3, and W4), reaching sensitivities hundreds of times deeper than IRAS. We have used WISE photometry to select an all-sky sample of objects which are extremely luminous. The objects are prominent in W4, but faint or undetected in W1 and W2 (W12drops). Followup spectroscopy of ~ 100 sources shows over 70% of W12drops have redshifts > 1.6, which with OT1 PACS and SPIRE photometry of 27 sources leads to over 1E13 solar luminosities, with ~ 10% exceeding 1E14 solar luminosities. High resolution adaptive optics imaging shows these objects are unlensed. We request 47.3 hours of Herschel time to complete the all-sky sample of the brightest 185 W12 drops, fulfilling the primary WISE objective of finding the most extreme luminous IR galaxies in the Universe. These superlative objects will be the most fruitful for detailed studies of the physics of star formation, AGN fueling, and feedback in the most active galaxies.

Stephan's Quintet (SQ) is a compact group of galaxies, where tidal interactions have brought large amounts of gas into the intergalactic medium (IGM). Spitzer IRS observations revealed an unusually bright H2 line emission from a giant (40 kpc long), X-ray emitting shock attributed to a high-speed (1000 km/s) galaxy collision. The extreme H2-to-PAH flux ratio (1000 times more than star-forming galaxies) suggest that H2 is predominantly excited by shocks rather than UV heating from star-forming regions. From our OT1 P2 project, we recently obtained SPIRE images of SQ, revealing for the first time the cold dust associated with the warm H2 gas in the shock. However, the large SPIRE beams do not separate star-forming regions from shocked gas. To confirm what fraction of the dust emission comes from the shock, we propose PACS observations with higher angular resolution. These observations are further motivated by our recent PdBI CO(1-0) observations, which break the SQ shock in large complexes (3-5 kpc in size) with a range of line widths (40-200km/s). Some of them could be sites of star formation. PACS is the only instrument providing the sensitivity and angular resolution to quantify star formation on these scales. With the proposed observations, for the first time for IGM gas, we will be able to (1) calibrate the CO to H2 conversion factor using dust emission and estimate the total cold gas content of the CO complexes, (2) study the impact of turbulence on star-formation efficiency, and (3) constrain the dust size distribution. The results will have important consequences on our understanding of the energetics and the role of dust in cooling the IGM gas in high-redshift mergers, and in the formation of galaxies.

Starburst-driven outflows -superwinds- are ubiquitous in galaxies with intense star-formation and are a complex phenomenon, literally requiring observations at every wavelength to unravel their energetics, outflow rates, and cosmological significance. We propose here, as part of a comprehensive study to understand the entrainment of material in winds, [OI] and [CII] spectroscopy with PACS of the "cap" in M82. The cap is a region of emission well out of the plane of M82 and provides the most robust evidence that winds escape. But this may not be true. Only through an understanding the how entrainment cools the wind material can we say this with any surety. That requires understanding how the wind energy is dissipated in entrained material like the cap. The proposed PACS observations follow our recent and puzzling detections of bright H2 rotational and [SiII] line emission with Spitzer IRS in the cap, as well as a non-detection of CO(1-0) and (2-1) in deep spectroscopy with the IRAM 30m telescope. The far-IR [OI] and [CII] lines will uniquely probe the relative contributions of the shock vs. photo-ionization in the cap. The cap offers a particularly clean environment to model the wind-cloud interaction. The results will be a critical test of a detailed physical model we are developing to describe the dissipation of kinetic energy in multiphase winds. This is a crucial step in understanding less detailed, high-redshift observations of superwinds, as well as the importance of winds for the evolution of galaxies and the inter-galactic medium.

Observations of ionized and massive neutral gas (HI) outflows in radio-galaxies (RGs) suggest that radio-jet feedback has a galaxy-scale impact on the host interstellar medium (ISM). Our recent results from Spitzer IRS spectroscopy of a small sample of 8 HI-outflow RGs show that all of them have bright H2 line emission that cannot be accounted for by UV or X-ray heating, and that the H2 gas is extremely turbulent, with H2 S(1) line FWHM = 450-720 km/s. We suspect that the radio-jet is injecting large amount of turbulent kinetic energy into the ISM, but little is know about the role of the turbulence in forming cold neutral gas from warm gas, and in regulating star formation. Our calculations and shock modeling predict that in turbulence-dominated gas, this line could be brighter than the H2 S(1) line. We propose PACS [CII] spectroscopy to test this, and probe an important missing piece of the ISM line cooling. These sources span a large range of IR luminosities and jet kinetic power, and provide ``clean'' environments where jet-induced shocks and turbulence seem to govern the physical state of the gas. This will uniquely complement our accepted (OT1, P1, not scheduled yet) PACS [OI] and SPIRE spectroscopy on these sources, allowing us to estimate the relative contributions of the shock vs. photo-ionization. Such a detailed understanding of the energetics of radio-jet feedback is crucial to interpret high-redshift observations and input numerical models of galaxy evolution.

The archetypal ultraluminous infrared galaxy Arp 220 revealed a remarkably rich spectrum in Herschel SPIRE FTS observations, including luminous emission from warm CO and water. The spectrum also revealed the presence of a massive molecular outflow, traced by P Cygni line profiles in the molecular ions OH+ and H2O+, and possibly H2O. Comparison of the column densities of these ions relative to water (and the absence of the ion H3O+) indicated that only an XDR powered by an X-ray-luminous AGN is capable of explaining the relative abundances; that these molecular ions are the same species that are participating in the outflow suggests there may be a connection between the AGN and the outflow.

Because the FTS did not resolve the lines, only limited information regarding the outflow and the column densities could be derived from the saturated lines. To much more accurately characterize both the physical and chemical state of the gas (in particular the water chemistry) and the mass and energetics of the outflow, we propose to obtain HIFI observations of a number of H2O, H2O+, and OH+ emission and absorption lines (including those exhibiting P Cygni profiles). In addition, we propose to observe two fairly strong unidentified emission lines, which fall quite close to the expected frequencies of the HCN and HCO+ J=6-5 rotation lines. Lower-lying transitions of both species have been measured from the ground; the apparent velocity offsets from the expected positions may be the consequence of complex emission and/or absorption profiles. In the case of HCN, the FTS data have established that the J=13-12 line and above are seen in absorption.

The origin and evolution of the dust in early-type galaxies are two of the key questions to understanding their evolution at late times. The two main scenarios to produce their dust are in situ formation from the winds of cool giants and the accretion of small, gas-rich satellite galaxies. The later scenario appears to be the only viable explanation for the several orders of magnitude variation in the amount of dust at fixed stellar mass, as in situ formation implies that the dust content should approximately scale linearly with stellar mass. Yet our demographic studies of a well-selected sample of early-types show that dust is present in roughly half of them, which implies a very high merger rate given the expected short lifetime of dust in their hot ISM. We propose SPIRE photometry of 11 of the 45 early-type galaxies in our previous Spitzer and HST studies. These 11 galaxies have 3-channel MIPS photometry, HST images, and deep ground-based photometry and spectroscopy. There are 12 additional galaxies that meet these criteria and already have executed or planned observations. Our goal is to measure the cold dust masses for these galaxies and thus determine the likelihood that the dust originates from minor, gas-rich mergers. The SPIRE data are critical to accurately measure the dust masses in these galaxies as the vast majority are active and thus may have a substantial hot dust component that biases mass estimates from the existing, shorter-wavelength IR photometry. These data will be combined with archival SPIRE data for the remaining 12 galaxies with detections in our Spitzer study to measure the distribution of dust masses our representative sample of early-type galaxies and thereby better constrain the origin of the dust.

Dust grains ejected into the hot interstellar gas in group-centered elliptical (E) galaxies are destroyed by ion-grain collisions, but during their short lifetime (10 Myrs) the grains emit sufficiently in the far infrared (FIR) to be easily observable. Remarkably, against this background emission, observations with Spitzer discovered many E galaxies with much stronger and spatially extended FIR emission from colder grains 5-10 kpc distant from the galaxy cores. Extended excess cold dust emission is interpreted as evidence of recent feedback-generated AGN energy outbursts in these galaxies, visible only in the FIR, from buoyant gaseous outflows from the galaxy cores. With Spitzer a quasi-radial plume of AGN-heated gas is resolved in only one galaxy, but marginally resolved in others. We request Herschel observations of a small sample of these E galaxies to confirm the existence of excess, spatially extended dust and to possibly spatially resolve more quasi-radial buoyant dusty gaseous plumes. Based on a detailed analysis of Spitzer data, our sample for Herschel is chosen to maximize the likelihood of discovering new FIR evidence of post-feedback events from massive galaxy-centered black holes.

We propose to use the unique power ot Herschel to analyze the most extreme resolvable photdissociation regions, i.e. those at low metallicity and energized by hard radiation. With a modest investment of observing time, we will probe a unique part of parameter space, providing a strong lever arm to test the validity of PDR models. Furthermore, the conditions of low metallicity and hard field are exactly those which are more prevalent in the early universe compared to today, and increasingly important to understand the interstellar medium of early galaxies. The regions we propose to study in detail in the local universe are a unique window into how the first stars affected their environments, which we will not easily study at this resolution.

The only PDRs close enough to resolve their structure and at low metallicity are in the Magellanic Clouds. There are only a few nebulae in the Clouds that are clearly energized by the extremely hard radiation from Wolf-Rayet Stars, and we will analyze two in each galaxy, which combined with our existing Spitzer and Herschel data will provide unprecedented information on PDR physics throughout the universe.

We have shown that SPIRE is capable of exploring high-redshift galaxies spectroscopically, provided those galaxies are sufficiently bright.

Here, we propose to exploit its wide wavelength coverage to study the powerful diagnostic rest-frame FIR cooling lines from a sample of 48 bright, lensed - but intrinsically typical - submm galaxies (SMGs). Our targets span 1 < z < 3.1 and 11.5 < log L(FIR) < 13.5, and are selected from panoramic Herschel imaging surveys that are uniquely capable of providing a large, reliable sample at S(350um) > 200mJy, with excellent ancillary data.

We will detect or place sensitive limits on key atomic and ionic cooling lines, e.g. [C II], [O I], [O III], and combine these with ground-based observations of 12CO, 13CO, C I and dense-gas tracers to perform a detailed analysis of their ISM and thence understand their energetics and temporal evolution. Using these data we will:

1) empirically constrain the interplay between gas cooling and heating in IR galaxies, mapping the evolution of the star-formation efficiency, exploiting our large sample to separate dependencies on L(FIR) and z, and thereby establishing fundamental relationships for the IR galaxy population;

2) conclusively address the issue of the contribution of AGN to IR galaxies;

3) coadd spectra in the rest frame to delve up to sqrt(48)x deeper than an individual spectrum, to confirm/quantify the signature of powerful feedback via OH molecular outflows, and add powerful diagnostics, e.g. H2O, [O I] and high-J lines, allowing a complete characterisation of the entire FIR spectrum.

Goals 1 and 3 drive the requirement for a sample of 48 SMGs. All our goals require Herschel and cannot be addressed by other facilities.

We stress that the scientific legacy of ISO and Spitzer has in large part been based on the wealth of data in their spectroscopic archives and the same will likely be true for Herschel.

LIRGs and ULIRGs are found to deviate strongly from the mass-metallicity relation. More specifically, at a given stellar mass, the metallicity of LIRGs and ULIRGs, as inferred from optical spectroscopy, is much lower than the value expected from the mass-metallicity relation observed in normal star-forming galaxies. This "metallicity anomaly" of LIRGs and ULIRGs has been ascribed, by many models, to the inflow of metal poor gas, from the galaxy outskirts, induced by the tidal forces associated with these merging systems. However, an alternative possible scenario is that in these dusty systems optical spectra only probe the outer, metal poor regions, while the bulk of the gas is actually metal rich, but it is heavily absorbed by dust.

We propose a definitive test of the scenarios discussed above by obtaining an independent, extinction-free measurement of the gas metallicity in a sample of LIRGs-ULIRGs, by exploiting newly developed far-IR metallicity diagnostics. In particular, we have recently shown that by measuring the relative intensities of the fine structure lines [OIII]52um, [OIII]88um, [NIII]57um and [NII]122um, it is possible to constrain the gas metallicity with high accuracy and in a wavelength range nearly unaffected by dust extinction. If these far-IR diagnostics confirm the low metallicities observed in the optical spectra, this would support models envisaging inflow of metal poor gas in interacting systems. If, instead, the far-IR diagnostics measure much higher metallicities, this would favor the scenario where the bulk of the gas is metal rich, but heavily absorbed, and it has been elusive to optical observations.

Understanding the formation and evolution of the first quasars, their supermassive black holes and host galaxies is one of the most important goals of both observational and theoretical astrophysics. In the last decade there has been immense progress in the discovery and study of z>6 quasars but since the discovery of SDSS J1148+5251 with z=6.42 by Fan et al(2003) almost a decade ago no quasar has been discovered with z>6.5. Recently, using data from the UKIDSS survey we have discovered a bright (K[Vega]=17.7) quasar ULAS J1120+0641 (Mortlock et al, 2011) which is the most distant quasar currently known at z=7.085, smashing the previous record of z=6.44 by a large margin. Furthermore, in the last few months, using data from the ESO VISTA public surveys, we have discovered three more quasars at z>6.5, with similar rest frame UV luminosity as ULAS J1120+0641 and redshifts of z=6.6, 6.8 and 6.9 respectively. Observations with the Plateu de Bure Interferometer of the z=7.085 quasar ULAS J1120+0641 have already revealed a significant detection of the [CII] 158micron cooling line which is the dominant interstellar medium (ISM) gas cooling line in star-forming galaxies confirming the presence of an ultraluminous star-forming galaxy associated with this quasar. In this proposal we shall carry out PACS and SPIRE photometry in the wavelength range 100-500microns corresponding to 12-60microns in the rest frame in this sample of four z>6.5 quasars with the goal of measuring the shape and luminosity of the FIR continuum in these primeval objects. These measurements will provide unique constaints on the star-formation rate, dust mass and dust temperature of the earliest massive star-forming galaxies.

We propose PACS [CII], [OI] and [NII] spectra to determine the source of heating for the cool (20-300 K) gas in an isolated, quiescent gas filament in the Brightest Cluster Galaxy (BCG) NGC-1275, the brightest of all cluster cool-core galaxies. The heating mechanism of this cool gas in BCGs is not well understood, It is also crucial to understanding analogous "negative feedback" processes in star-forming galaxies at high redshift. In combination with our SPIRE spectroscopy, and other deep multi-wavelength measurements, the proposed observations will provide a unique data set that will allow us to develop a consistent physical picture of the processes that energize the filaments. NGC-1275 is the only cool-core BCG where we can separate the quiescent filaments from the nuclear region influenced by the AGN. This will allow us to directly compare the heating of cool gas in these filaments with that in the nuclear region.

We propose Herschel/SPIRE photometric observations of dust continuum emission in a sample of 19 weak line quasars (WLQs) at 2<z<5. These objects have weak or undetectable UV emission lines, with typical rest-frame Lya +N V equivalent widths <15 A. However, their broad band AGN continuum emission from is similar to that of normal radio-quiet/intermediate quasars, indicating that the weak UV line features are unlikely to be due to a relativistically boosted continuum. It is possible that these WLQs are young AGN systems, in which the emission line regions associated with high ionization lines have not yet fully formed. In this proposal, we request a systematic survey of the rest-frame far-infrared (FIR) dust continuum emission with SPIRE at 250 um, 350 um, and 500 um. The FIR emission from 30 to 60 K warm dust provides the most reliable estimates of star formation rates in the quasars/galaxies at high redshifts. Our goals are i) to determine the dust temperature, dust mass, and FIR luminosity of each object by fitting the SPIRE flux densities to an optically thin graybody model and constrain the star formation rates in these WLQs and ii) to obtain the mean FIR emission of the WLQs and understand how it compares to the normal/strong emission line quasars. The observations will be a crucial test of the hypothesis that if these WLQs are at a young evolutionary phase, in which the central AGN activity has just turned on and intense star formation is ongoing in the quasar hosts.

Our group have been carrying out a systematic survey of the star formation and ISM properties in the host galaxies of z~6 quasars, and strong millimeter dust continuum and highly-excited molecular gas have been discovered in the host galaxies of about 30% of quasars at z~6, indicating the presence of massive star formation coeval with rapid supermassive black hole (SMBH) accretion in these earliest quasar host galaxies close to end of cosmic reionization. In this proposal, we request Herschel/SPIRE photometric observations of the rest-frame FIR continuum emission from three of the millimeter bright z~6 quasars. The FIR emission from star formation-heated warm dust provides the most reliable measurement of the star formation rate in the quasar host galaxies at the highest redshift. The SPIRE observation samples the peak of the FIR SED from quasars/galaxies at z~6, and thus, are critical in the study of dust temperature, dust mass, FIR luminosity and star formation rate in these ealiest quasar-starburst systems. We have an approved ALMA Cycle 0 project of image the [C II] fine structure line and 1mm dust continuum emission and measure the distribution of the star formation in these three objects (and another two z~6 quasars observed in an existing Herschel Key Program). The accurate measurements of star formation rates with SPIRE and spatial distribution/surface densities with ALMA will put key constraints on the early growth of the quasar spheroidal host galaxies at the earliest epoch. We also require PACS photometric observation of the 100 um and 160 um dust continuum emission from one of the three objects, J2310+1855, at z=6.002. This object is a rare Low ionization Broad Absorption Line quasar, but show very bright millimeter continuum and molecular CO line emission from the quasar host. The PACS observation will measure the rest-frame mid-infrared continuum emission and allow us to investigate the emission properties of the AGN-powered hot dust torus in the LoBAL systems at the highest redshift.

In order to understand the physics and evolution of galaxies, accurate measurements of their gas content are absolutely crucial. The standard method is to estimate the mass of the atomic phase from the 21-cm line and the mass of the molecular component from the CO 1-0 line. Recent Planck and Fermi results imply that there might be as much CO-dark molecular gas as is detected in the CO line. The existence of a significant phase of the ISM that is not traced by the CO/HI method has obvious implications for extragalactic astronomy, because all present and planned observational programmes to connect the star-formation rates of galaxies to their interstellar gas reservoirs are based on the standard CO/HI method.We have recently used Herschel to observe M31, the other big spiral galaxy in the Local Group, in five photometric bands. By comparing the dust column-density to the gas column-density estimated from the CO/HI, we have shown there are regions in M31 where there also appear to be substantial amounts of dark gas. The only way to unambiguously demonstrate its presence is to detect it directly. We therefore propose to observe 400-arcmin2 of M31 in the [CII] 158-micron line. These observations will provide a clean test of the 'dark gas' hyopthesis. This large survey of [CII] over a significant area of the closest big spiral, together with the existing CO and HI maps, will provide the most comprehensive dataset for studying all phases of the ISM in a normal spiral galaxy until SPICA. Together with the existing Herschel observations, the new data will make possible many projects to study the astrophysics of the ISM and the connections between star formation and the different phases of the ISM.

Models and observations have established the importance of major mergers in reshaping spirals and fueling starbursts and supermassive nuclear black holes, but much less is known about the redistribution, heating and the fate of dust and gas during the merger event. The Mice (NGC4676) is a rare pair of local galaxies caught in the early merger stage of heating a vast amount of molecular gas in one merger companion while generating intense starbursts in the other companion. Roughly 170 Myrs after the first encounter, the two companions appear optical similar but show extremely different contributions from the PAH, the warm and the cold molecular gas emission, so that the responsible heating mechanism remains a mystery. The proposed PACS and SPIRE spectroscopy, together with our Spitzer IRS data, will unveal the origin of this dichotomy in the ISM (e.g. the relative contributions of shocks versus UV heating). A strong tracer for shock excitation is an enhanced [OI] compared to H_2 and [CII] emission as well as an enhanced excitation of the high-J (>6-5) CO transitions and the detection of water lines. The combined power of high spatial resolution mid-, far-infrared imaging and spectroscopy as well as our CO interferometry, NIR, and optical data allows us to link the dominant coolant of the interstellar medium, PDRs, shocks, and ionized gas properties to the starlight, the dust, the warm and the cold molecular gas. The Mice galaxies offer an ideal test case for studying the interplay between star-formation and the ISM in a interaction driven environment. Herschel observations of this galaxy pair will provide a view on a rare local example of a brief phase (~100 Myrs) in the evolution of a major merger where shocks dominate the H_2 emission and the individual nuclei have extremely different spectral and physical properties.

We propose to carry out a HIFI survey of the fundamental transition of hydrogen fluoride (HF) at 1.232 THz toward 16 nearby IRAS-bright galaxies to probe their ISM physical conditions. Our proposal is motivated by recent Herschel observations revealing ubiquitous absorption by HF in the Milky Way galaxy. The HF J=1-0 transition has been observed in the spectrum of almost every bright continuum source in the Galactic plane and reveled to be an extremely sensitive probe of the diffuse molecular gas. We intend to make use of this unique probe by conducting a high spectral resolution (10-20 km/s) HIFI absorption survey toward continuum-bright external galactic nuclei exhibiting a wide range of physical properties (AGN, starbursts, mergers). HF is chemically very strongly bound and therefore resistant to photodissociation. Our study is facilitated by this resistance of HF molecules to destruction, which will occur in the extreme environments in the galactic nuclei. HF will thus be a very useful probe in regions of the ISM where more traditional gas probes, such as CO, are more prone to error (e.g., the use of the X-factor). With the simplifying assumption that all fluorine is likely to be locked up in HF, and that the HF molecules will reside in the ground rotational state, we can measure the hydrogen column density and mass of the nearby IRAS-bright galaxies. Observations of the local galaxies proposed here is the first step toward using HF as a tracer of the gas in high-redshift galaxies. By looking at extragalactic continuum-bright nuclei, we will also be able, through the use of the HIFI Wide Band Spectrometer, to simultaneously search for absorption through the Milky Way halo cloud population. Here, the rapid formation rate of HF and its strong molecular bond will allow us to detect HF absorption toward the tenuous and quiescent mostly HI clouds making up the galactic halo. These diffuse, cold regions may not otherwise be detectable in CO emission or other commonly uses tracers.

Quasar mode feedback is thought to be a crucial ingredient in galaxy formation for luminous merging and star-bursting systems at high redshift. The energy from the emergent active nucleus is thought to cause significant gas outflows, reducing the available free gas reservoir for future star formation. It is currently unknown which observational state best corresponds to the stage at which this "blowout should occur. We intend to test one possible source population for this transition phase, by studying the dust content in a small, statistically complete sample of K-band selected reddened quasars from the AUS survey. All lie in the redshift range 1.5<z<2.5, the peak of quasar activity in "typical" galaxies. If the model is correct these galaxies should be in transition from actively star forming to passively heated dust, and should therefore show both far infrared colour and luminosity correlations with optical colour.

A remarkable result to date is our recent SHINING detection of the [CII] line with PACS in the ultra-metal-poor galaxies: IZw18 and SBS0335-052 (1/40th and 1/50 solar metallicity) giving us the best opportunity to study the star formation and ISM properties under the most extreme metal-poor conditions we have in our local universe - conditions similar to primordial ISM at very high redshift. SBS0335-052 and IZw18 are the most metal-poor galaxies that will ever be observed by Herschel. In spite of similar metallicities, the 2 galaxies are very different in star formation rates and MIR and FIR luminosities, suggesting that metallicity is not the most important parameter controlling star formation activity. We ask here for complementary [OI] 63 $\mu$m and [OIII] 88 $\mu$m observations to be able to interpret the [CII] detection in terms of ionised and neutral gas properties. These galaxies are not detected in CO and we believe that the [CII] is probing the molecular gas not traced by CO - the 'dark molecular gas' which could be a significant reservoir of fuel for the star formation in low metallicity galaxies. Our [CII] observations along with these followup lines, can provide a means to unveil this suspected reservoir of CO-free molecular gas. The [CII] detection along with these 10.2h of observations requested in this proposa, will shed unique, new insight on extremely low metallicity conditions for star formation and also help provide a standard calibration for getting a handle at the molecular gas reservoir in the high redshift lowest metallicity galaxies which will be a focus for ALMA studies.

The role of galactic winds in gas-rich mergers is of crucial importance to understand galaxy and supermassive black hole evolution. In the past year, our group has had three major scientific breakthroughs in this area: (1) The PACS discovery of powerful molecular OH winds in several ULIRGs, including Mrk 231. (2) The independent discovery from mm-wave CO interferometric observations in Mrk 231 of a spatially resolved molecular wind with estimated mass outflow rate ~4x larger than the star formation rate. (3) The detection from optical IFU observations of an equally powerful wide-angle neutral-gas outflow in this same object. These powerful outflows may be the long-sought "smoking gun" of quasar mechanical feedback purported to transform gas-rich mergers. Indeed, we see possible trends of increasing outflow velocities and decreasing depletion time scales with increasing AGN luminosities in our PACS data. The approved OT1 extension of this program to quasar-dominated ULIRGs will allow us to test these trends. However, by design, this sample does not contain any "classic" IR-faint QSOs in the critical late merger phases when the quasar has finally gotten rid of its natal cocoon and the effects of feedback are predicted to subside. So here we request 37.2h to obtain high-S/N OH 119 um spectra of 5 IR-faint quasar-dominated late stage mergers. We have a comprehensive set of multiwavelength data on all of these objects, including crucial spatially resolved optical neutral-gas absorption spectroscopy. We will look for trends between the basic measured properties of OH (incidence of absorption, kinematics, column densities) and host/evolutionary indicators. In cases of kinematic match between OH features and spatially resolved neutral-gas clouds, we will be able to infer the masses and kinetic energies of these outflows. Measured velocities in excess of ~1000 km/s or inferred mass outflow rates much larger than the star formation rates would be telltale signs of AGN-driven winds.

We propose to extend our OT1 PACS imaging survey of galactic winds in nearby star-forming galaxies to the poorly explored but critically important low-mass end of the galaxy mass function. Following our OT1 strategy, we will obtain very deep PACS 70/160 micron data to map the detailed distribution of cold (T<100 K) dust in a small but representative sample of dwarf galaxies that are known to host outflows. These data will be compared to state-of-the-art, 3D numerical simulations of superwinds and predicted PACS fluxes. Direct and indirect evidence shows that dust is present on large (kiloparsec) scales in outflows in some starburst galaxies. However, this dust has never been mapped at wavelengths of 70-160 microns, and its geometry, mass, and energy are almost completely unknown. Recent spectacular SPIRE results on M82, as well as our own Spitzer IRAC 8-micron and MIPS 24-micron maps of the targeted wind galaxies, suggest that this survey will yield exciting new insights on the cold dust in these outflows. We will ascertain the significance of dusty superwinds in the context of outflow physics and the impact of the outflows on the host galaxies and the IGM. We will compare the distribution, mass, and energy of the cold dust to optical emission-line and absorption-line, mid-infrared, X-ray, and radio data compiled by us and other groups. As in OT1, we note that several of our targets are being mapped with PACS and SPIRE as part of key programs (KPs). However, the objectives of these programs are heterogeneous and often neglect the importance of outflow science. This is reflected in the depth of the observations at the critical shorter wavelengths, near the peak of the IR SED: the PACS KP data will not be able to detect the FIR emission expected from a M82-like wind in our galaxies. The proposed PACS survey will go nearly an order of magnitude deeper than the KP data and will complement the SPIRE portion of the KPs, while providing many advantages over the SPIRE data.

Mechanical feedback from AGN-driven winds has been purported to play a central role in the evolution of galaxies. However, past searches for AGN winds have been heavily biased, selecting the brightest sources in bands affected either by obscuration and/or contamination from the host galaxy light, and incomplete, probing only the ionized gas phase of these winds. Remarkably, recent results from our group and others have demonstrated that the neutral and molecular components of AGN-driven winds often dominate the mass, and thus dynamics and energetics, of these winds. To address these limitations, we have been conducting an extensive multiwavelength campaign, including crucial spatially resolved optical neutral-gas absorption spectroscopy, of all AGN detected in the very hard X-rays (14-195 keV) by Swift-BAT. The Swift-BAT survey is the least biased all sky survey for AGN with respect to host galaxy properties and obscuration in the line-of-sight, and thus it is superior to past surveys for understanding the role of AGN-driven winds in galaxies. Here we request 35.3 hrs to obtain high-S/N OH 119 um spectra of all BAT-AGN within the Local Volume to characterize molecular gas in/outflows in these systems. A distance limit of <50 Mpc is selected to provide the best possible scale (<200 pc/arcsec) while also sampling the AGN luminosity function up to quasar-like values without favoring IR-bright systems due to the need for high-S/N data at ~120 um. We will look for trends between the properties of OH 119 um (incidence of absorption, kinematics, column densities), the AGN (e.g., luminosity, accretion rate), and the host (e.g., morphology, star formation rate, extinction). In cases of kinematic match between OH features and spatially resolved neutral-gas clouds, we will be able to infer the masses and kinetic energies of these flows. Measured blueshifted velocities in excess of ~1000 km/s or inferred mass outflow rates much larger than the star formation rates would be telltale signs of AGN-driven winds.

Recent results based on far-infrared (IR) data obtained with Herschel strongly suggest the existence of two modes of star formation that apply to low and high-redshift galaxies: a quiescent mode for disks (or main-sequence galaxies) and a starburst mode probably associated with more efficient nuclear, compact star formation. This dichotomy implies that the properties of the inter stellar medium (ISM) in these two types of systems must be substantially different. We have used the mid- to far-IR colors of galaxies as a proxy for their compactness to select a sample of local, compact luminous IR galaxies ((U)LIRGs; LIR >= 10^11 Lsun) from the IRAS 12-micron sample. Our sample of 73 compact (U)LIRGs includes both Seyfert galaxies as well as purely star-forming systems, and therefore is not biased towards active galaxies only. We will observe the key far-IR [CII]158, [OI]63, and [OIII]88 micron emission lines with Herschel/PACS and use models of photo-dissociation regions (PDRs), shocks, X-ray dissociation regions (XDRs), and dusty AGNs to derive the main physical parameters of the ISM in this important class of systems, which are not being targeted by any Herschel project. Our proposed galaxy sample bridges the gap between other studies focused on the analysis of local galaxies with a range of IR luminosities, mid- to far-IR colors, or more spatially extended IR emission, providing a wider view of the star formation and nuclear activity in local IR-bright galaxies in extreme environments, and thus adding a significant contribution to the Herschel legacy. The total time requested for achieving this goal is 89.8 hours.

We require Herschel PACS and SPIRE to study the ISM and cold dust component of a gas-rich, local LIRG undergoing inside-out disk-building -- HIZOA J0836-42. Spitzer reveals this galaxy to be PDR-dominated with gas and stellar properties, as well as specific star formation, more in common with z~1 systems than local LIRGs. We see evidence of neutral gas funneling into the mid-IR star-forming disk. Our observations will provide crucial (and unique) spatial information of the ISM and cold dust that may be common to z~1 "scaled-up" disk galaxies that have large reservoirs of neutral gas that they are actively converting into stars, in an extended disk. Knowledge of the active enrichment and metamorphosis of the ISM further out in the disk due to "new" star formation will enable us to form a cohesive picture of this mechanism of star formation and the role of gas, dust and (old and new) stars. We will search for evidence of "dark" molecular hydrogen inhabiting PDRs and making a hidden (and potentially crucial) contribution to the molecular mass that fuel in these systems. We can achieve this by mapping the cool dust component across the HI disk and obtaining maps of the key cooling lines, [OI]63 and [CII]158. These data will be complementary to our broader multi-wavelength study, and motivate future planned observations that aim to address our main science goal: understanding how the components of star formation (gas, dust, stars) interact and drive the fundamental gas-to-stars evolutionary cycle for galaxies in the early universe.

We plan to investigate the interplay between the phases of the interstellar medium (ISM) and their evolution near star forming regions as a function of galactocentric distance by observing the far-infrared (far-IR) fine-structure lines of [CII] 158 micron, [OI] 63 micron and 146 micron, [NII] 122 micron,and [OIII] 88 micron in selected regions in the local-group galaxy M33. The transformation from atomic gas to molecular clouds and their subsequent destruction due to star formation is still poorly understood. Feedback from the young massive stars could heat the surrounding gas and thus hamper further star formation or compress the surrounding gas and thus increase the star formation effiency. The sequential evolution of cloud formation, star formation, and cloud destruction might depend on the internal as well as the external environmental conditions such as pressure, surface density, and metallicity, which change with galactocentric distance. The [CII], [OI], [OIII], and [NII] lines provide the best tools and M33 the optimal galaxy for this study. This proposal, for which we ask 12.5 hours observing time, is a follow-up project to the HerM33es key project.

We propose to make PACS and SPIRE photometric mapping observations to obtain far-infrared (FIR) spectral energy distribution of the extended structures of the two merger galaxies NGC2782 and NGC7727, in which mid-infrared (MIR) observations with the Infrared Camera (IRC) onboard AKARI indicate the presence of PAH, and to investigate the dust processing associated with the merger event. Both galaxies show intriguing features at the mid-infrared band sensitive to the PAH features. The extended tail of NGC2782 seen at 7 micron is thought to have been produced by collision of a low-mass galaxy with the main galaxy about 200 Myr ago, while that seen in NGC7727 is a relic of the merger event of 1.2 Gyr ago. Both galaxies offer a unique opportunity to study dust processing in the merger event in different time scales. We propose to obtain FIR data to compare with the MIR data taken with the IRC, which will allow us to investigate the life cycle of dust grains in the ISM associated with violent events.

We propose to measure FIR dust temperatures primarily for two X-ray absorbed, sub-mm bright, QSOs that may prove play the role of the `Rosetta Stone' in relating the sub-mm and X-ray backgrounds. Of 15 Chandra X-ray QSOs in the central ~100 sq. arcmin of the William Herschel Deep Field (WHDF), Bielby et al (2011) found that the only 2 that are identified as sub-mm sources are these absorbed QSOs at z=1.33 and z=2.12, with the latter being a narrow-lined Type 2 QSO. 11 X-ray unabsorbed QSOs were all undetected by LABOCA at 870 microns. Similar results were found previously by Page et al (2004). On the other hand, Hatziminaoglou et al (2010) recently found that many unabsorbed QSOs are clearly detected at 24-500 microns indicating warmer dust temperatures. One possibility is that the presence of cold gas and cold dust are correlated. This would predict that absorbed QSOs may only contain cold dust and we propose to test this prediction via PACS and SPIRE observations. If more cold gas does imply more cold dust then the Compton-thick QSOs needed to explain hard X-ray background may also explain the sub-mm background.

We propose to observe a small sample of nearby major mergers in three different merging stages with Herschel PACS and SPIRE photometers. The observations will allow us to derive the dust surface density and from this the total gas surface density. Together with already available tracers of the SFR (Spitzer 24 micron and GALEX FUV) we can study the Kennicutt-Schmidt law. High resolution data of the atomic gas content (partly already available and partly applied for at the EVLA) allow us furthermore to make a distinction between atomic and molecular gas. The derivation of the total gas mass via the dust emission involves less serious uncertainties than the use of CO as a tracer of the molecular gas.

With these observation we aim to address the open question why merging galaxies form stars at about a 10 times higher rate compared to their gas mass than quiescent galaxies. Our recent numerical models explain this by a higher turbulence which make the step from low-density to high-density (star--forming) gas more efficient. It makes specific prediction about the efficiency of the conversion from atomic to molecular gas, which directly affects the ratio between SFR and gas mass, as a function of merger stage. The selection of our sample and the proposed observations will allow us to test the predictions of the simulations and provide therefore an opportunity to improve our understanding of the physical processes underlying star-formation and of the cosmic star formation history

The so called Hickson Compact Groups (HCGs) occupy a unique position in the range of galaxy environments found in the local universe. While their density enhancements are high, close to those seen in rich clusters, the over-densities appear to be more locally contained. Dynamical interactions between the galaxies in the groups lead to consumption of the available gas, star formation, and a rapid evolution compared to field galaxies. It has been shown that HCGs contain significant amounts of dust, which has so far hampered a detailed understanding of those objects based on optical observations alone. Based on recent Spitzer observations, we have embarked in the first multiwavelength analysis of how groups affect galaxy evolution. We used the state-of-the-art theoretical models in order to interpret the complete spectral energy distribution of the galaxies from the UV to the IR, and compare them with samples of field galaxies and interacting systems. However, due to the proximity among the various galaxies in groups none of the past far-IR facilities (IRAS, Akari) had the angular resolution necessary to trace the far-IR emission of the individual group members, essential to determine the global energetics and dust content of the systems.

We propose to obtain deep broad-band far-IR images of 20 HCGs at various stages of evolution for which UV, optical, near-IR, and mid-IR data also exist. Herschel observations with their unique depth and high angular resolution, will enable us a) to accurately calculate the far-IR luminosity, dust mass and temperature of galaxies in HCGs in order to examine how the group environment affects them and b) determine the total "dust budget" in the groups by detecting the cold intragroup dust, studying its temperature, clumpiness, and spatial distribution. The proposed program requires a modest investment of 13.3 hrs.

Absorption line systems in quasar spectra, especially the damped Lyman alpha (DLA) and sub-DLA absorbers, provide excellent venues for directly studying the interstellar medium (ISM) in distant galaxies, selected independently of the galaxy luminosities. DLAs/sub-DLAs provide most of the neutral gas reservoir for star formation at high redshifts. A few especially cold, dusty absorbers have been discovered using radio surveys and the Sloan Digital Sky Survey. These absorbers, far richer in dust/molecules than the general absorber population, give us rare opportunities to probe molecular gas and star formation at high redshift. Unfortunately, very few sub-mm observations exist for these unique quasar absorbers. Here we propose SPIRE spectroscopy of 5 quasars with strong absorbers that appear to have cold/dusty gas. The proposed data will efficiently cover a wide spectral range that is expected to be rich in transitions of many atomic and molecular species (e.g., C I, N II, CH+, CO, 13CO, C18O, H2O) at the absorber redshifts. These transitions will allow us to estimate molecular abundances, and physical conditions of the absorber gas such as temperature and density. Comparisons of these distant absorbers with Milky Way ISM will provide a step toward understanding how ISM evolves with time. The molecular lines will also give constraints on isotopic ratios such as 12CO/13CO, and the cosmic microwave background temperature at the absorber redshifts. Our data will also cover the redshifted [C II] 158 micron emission line, which can help to constrain the star formation rate in the absorber galaxies. The proposed data will thus provide several fresh insights into the stellar and interstellar content of distant galaxies, and pave the way for future ALMA observations. Additionally, the data will provide important constraints on the continuum SEDs of the background quasars. Herschel SPIRE is the only current instrument that can offer the wavelength coverage needed to efficiently observe the lines of interest.

One of the outstanding tasks in modern astrophysics is to uncover the physical mechanisms responsible for the observed tight correlation between super massive black hole mass, and host galaxy bulge mass and stellar velocity dispersion (M_BH-sigma relation). Numerical simulations invoke major mergers and interactions between massive, gas rich galaxies to reproduce the observed relation, along with the ULIRG number density, QSO luminosity function, black hole mass function and mass density. However, observational evidence for these suggested scenarios is either unavailable or inconclusive.

Here we propose to measure the far-infrared continuum and line properties of a unique sample of massive, dusty, obscured AGN, to reveal whether they are the descendants of ULIRGs and progenitors of massive elliptical galaxies. These 12 galaxies contribute around 10% of the total black hole accretion rate summed over a complete sample of nearly 17,000 local (z<0.07) galaxies, and thus represent a significant channel for black hole growth in the Universe. Their optical continuum suggests they underwent strong starbursts between 0.35 and 1Gyr ago. Their nebula emission line strengths, combined with a simple empirical model for the rate of decay of star formation following a starburst, predicts FIR luminosities during their starburst phase of 7e11-2e12 Lsun, implying that these were ULIRGS in the past. Herschel PACS+SPIRE observations will reveal whether this sample of unusual, dusty AGN is the much sought after ``transition'' phase between merger/ULIRG/starburst and elliptical galaxy.

The understanding of the interstellar medium (ISM) and star formation in the low-metallicity environment is crucial to constrain formation of stars and galaxies of the first generation. The local extremely low-metallicity galaxies (XMPGs) with Z<Zsun/20 offer the unique laboratory with nearly metal-free environment that mimics the condition in the early universe. Previous infrared studies have focused on their integrated properties due to their small sizes and faint brightness. The general conclusion is that they show dramatic different ISM and star formation properties from more metal-rich galaxies, and that a large diversity in the properties is also seen among XMPGs alone. The high resolution combined with its multiple far-IR bands of Herschel will revolutionize the study of ISM and star formation in XMPGs through the spatially-resolved images of dust properties (mass and temperature) and SFRs. By relating the dust and star formation properties to the local physical conditions, we can start to understand the underlying physical mechanisms that regulate ISM and star formation processes in the extremely low-metallicity environment. We propose to obtain deep map of the dust emission in three XMPGs with Herschel PACS and SPIRE photometer. These three objects are carefully selected to facilitate the spatially-resolved study, i.e. the large size and previous IR detections by Spitzer. Combined with a rich ancillary data, we will (1) model dust emission to derive dust properties and then relate it to the local physical properties; (2) derive reliable SFRs by combining IR-based obscured SFRs and UV-based unobscured ones, from which we then can understand the star formation processes at sub-kpc scales.

We propose deep five-band imaging with SPIRE and PACS of 10 of the most massive galaxy clusters in a 455 square degree southern strip surveyed by the Atacama Cosmology Telescope (ACT). Our targets lie at 0.3 < z < 1.1 and were identified by their 2mm Sunyaev-Zel'dovich Effect (SZE) decrements, which provide a redshift-independent mass selection, and confirmed with optical imaging. Herschel observations, building on X-ray, optical, near-IR, submillimeter, and radio data, will allow us to study how star formation within individual galaxy members and integrated across clusters is influenced by the process of cluster assembly in the most massive systems out to z ~ 1. We will also extract our targets' SZE decrement/increment spectra and mass profiles, providing useful inputs to the cross-calibration and interpretation of large SZE surveys. Finally, our observations will exploit the clusters' gravitational lensing for the detection of dusty background galaxies, down to flux levels that would otherwise be below the confusion limit of blank-field imaging. By combining PACS and SPIRE data with our ancillary observations, we will be able to determine photometric redshifts for these background galaxies sufficiently well to allow followup observations with ALMA, for which our fields' southern declinations are ideal, in order to understand the detailed physical properties of dusty star-forming galaxies at high redshift.

Large-scale filaments are home to about 1/3 of all galaxies in the universe. Their characteristics make them ideal environments for galaxy-galaxy mergers and interactions, leading to bursts of star-formation, visible in the infra-red (IR). So far, only a few studies of filament galaxies exist, and even fewer including mid- or far-IR observations. We propose to partially fill this gap in our knowledge of galaxy evolution by observing a 14 Mpc long filament of galaxies connecting two clusters at redshift 0.23, with PACS and SPIRE for a total time of 18.1 hours. Complemented with already available extensive optical spectroscopic (1413 galaxies) and multiwavelength photometric data (including mid-IR data from Spitzer for one cluster and part of the filament), the new Herschel data will allow us to determine the galaxy (specific) star-formation rates as a function of their location in the filament with respect to the two clusters. This will help constraining which physical processes are responsible for the excess of star-forming galaxies in the filament relative to both denser and less dense galaxy environments, discovered in our previous studies of this region (Fadda et al. 2008, Edwards et al. 2010a,b, Biviano et al. 2011).

The star formation activity in a present-day galaxy is strongly correlated with the environment in which the galaxy lives. Passive, spheroidal systems are preferentially found in the core of clusters, whereas star forming, late-type galaxies inhabit low-density environments, from the field to the outskirts of clusters. Therefore, galaxy clusters are the best places where to probe galaxy transformation. Different mechanisms can contribute in driving galaxy transformations by depleting the galaxy of its cold gas reservoir and decreasing the star formation activity. Ram pressure stripping, harassment and galaxy-galaxy collisions are likely to play a role but it is still unclear which of these are the dominant mechanisms driving galaxy evolution inside clusters. In the continuos gold rush toward the highest redshift galaxies the local environment has long been neglected. In this proposal we aim to study the star formation activity and the galaxy dust role in nearby galaxy clusters (0.04<z<0.07) as a function of environment by probing the broadest possible range of environments from the core of rich clusters to the outskirts, where the main processes modifying galaxy properties occur.

We propose to image 1 sq. degree regions centered on Abell 963 and Abell 2192 in PACS/SPIRE parallel mode. These two galaxy clusters have very distinct environments yet both are located at z~0.2, where the Butcher-Oemler effect (the fraction of blue galaxies near the cluster center increases with redshift) begins to show. To identify physical mechanisms driving galaxy evolution in clusters at this redshift, our team initiated a multi-wavelength study of Abell 963, a rich cluster with a high fraction of blue galaxies around z~0.2, and Abell 2192, a less massive cluster with a low dispersion at a similar redshift. With the goal of relating the star formation activity with the ISM content, we have obtained deep WSRT HI imaging data, which is unique to date at this redshift. Besides HI data, we have collected radio continuum, mid infrared, optical, and UV data to diagnose the ISM removal processes and to study detailed star formation histories. In addition, we will start a CO survey of the two clusters in the near future to measure the total cool gas mass. Our multi-wavelength survey area is large (> 10 Mpc in diameter on the sky) enough to include low-density environments where galaxies appear to undergo significant evolution. The Herschel data will allow us to map out the entire IR SED of various galaxy populations and also to study dust properties, which is essential for this study. We request 40.3 hrs of Herschel time to obtain 9 PACS/SPIRE scans over 1 sq. degree field centered on each cluster (18 scans in total) to achieve the enough sensitivity to detect L* galaxies in each cluster.

In massive galaxies the AGN at the core can have a profound effect on its host galaxy from their formation to the present day. This effect is particularly important in the cores of clusters of galaxies where the AGN is believed to be strongly suppressing the cooling of the hot intracluster gas that surrounds the brightest cluster galaxy (BCG). We propose to obtain PACS photometry and spectroscopy of four BCGs that have strong AGN characteristics ([OIII] line, MIR continuum and/or flat spectrum radio continuum). These four systems are the most extreme BCGs selected from a sample of over one thousand X-ray selected clusters and hence can be used to constrain the energetics and duty cycle of AGN in a statistically meaningful sample of clusters. The Herschel data will reveal important diagnostics of the individual AGN that can be applied to weak AGN in the larger sample.

Recent observations suggest a reversal in the star formation rate density relation at z>1 such that the average star formation rate in galaxies increases with increasing local galaxy density. Two high redshift clusters have shown an increased fraction of actively star forming galaxies towards the center of the cluster, albeit with small number statistics, but the epoch at which this transition occurs is poorly constrained. We propose a statistical study of the dust−obscured star formation activity in a mass-limited sample of 11 spectroscopically-confirmed clusters from z=1.1-1.8 with PACS imaging at 100/160 microns. With 54.7 hours of observing time, we will detect ~150 cluster galaxies down to 100 solar masses per year and many more field galaxies. Our sample spans the fundamental redshift range during which massive clusters show signs of transitioning from a stage of active formation to passive evolution. We will determine the role of the cluster environment on the evolution of infrared luminous galaxies as a function of redshift. These Herschel observations will allow us to map out the star formation activity in galaxy clusters and constrain their mass assembly epoch.

Massive clusters of galaxies have been found to date from as early as 3-4 billion years after the Big Bang. Cosmological simulations using the current cold dark matter model predict that these systems should descend from 'proto-clusters' - early overdensities of massive galaxies that merge hierarchically to form a cluster. These protocluster regions themselves are built up hierarchically and so are expected to contain extremely massive galaxies, progenitors of the quiescent behemoths observed in cores of the present day massive galaxy clusters. Observational evidence for this picture, however, is sparse because high-redshift proto-clusters are rare and difficult to observe. Here we propose to probe with Herschel SPIRE the very beginning of the cluster and massive galaxies formation process by observing 5 proto-clusters at 3<z<4. The aim of the project is to observe the entire Ultraluminous IR galaxy (ULIRG) population, dominating the bulk of the star formation at such high redshift, to compare the properties of the proto-cluster galaxies with those of field galaxies at similar redshift. Determining whether cluster galaxies differ from field galaxies when the proto-cluster was still forming, tells us whether any of the difference observed today is driven by nature as apposed to nurture.

We propose to measure the dust properties and far-iR star formation rates (SFR) of high redshift type Ia supernova (SN Ia) host galaxies to improve their use as cosmic probes. In fitting SN Ia light curves, we must fit both the intrinsic color variation of the SN and dust together, limiting their statistical precision. Using light curve fitting, SN Ia have been observed to have a wide range of dust values and laws, some that are very different from the Milky Way. Additionally, after correction, SN Ia light curves show a dependency on their ultraviolet (UV) specific SFR's (sSFR), however the UV is sensitive to dust and thus our UV SFRs might be underestimated. We propose to take PACS and SPIRE observations of 74 high redshift host galaxies of SN Ia discovered by the ESSENCE project. We will measure the dust mass and temperature, using this information to re-analyze SN Ia light curves and study their intrinsic properties. We will also measure the far-IR SFRs to look for correlations and dependancies of SN Ia's on their host galaxies. All of this information will be used to improve and refine our measurements of Dark Energy.

Using data from the NASA Wide-field Infrared Survey Explorer (WISE) mission coupled with deep optical spectroscopy, we have discovered a new population of dusty z~2 galaxies surrounded by large spatially extended Lyman-alpha emission (40-100kpc). These galaxies have redder mid-IR colors than any other high-z dusty populations, inferred IR luminosities of L_FIR>10^13, are unlensed, and are experiencing intense AGN/supernova feedback. These unique properties, and rarity on the sky, make them strong candidates for being one of the ``missing links'' in the evolution of massive ellipticals. They have opened up a new regime where spatially extended Ly-alpha and large amounts of dust are likely linked at the key transition from a dusty starburst to a QSO.

We request 5.6 hours to obtain Herschel-PACS and SPIRE imaging of *all* 18 spectroscopically confirmed WISE Ly-alpha blobs. Herschel is the only facility that fully probes the peak of the bolometric emission at this redshift. These observations are required in order to 1) derive precise FIR luminosities 2) place robust constraints on the starburst and AGN components 3) study how feedback effects the shape of far-IR seds at high-z 4) uncover what is driving the winds responsible for powering the Ly-alpha clouds around these dusty galaxies and 5) place this new class of extreme object in context with the other well studied z~2 dusty galaxies.

We propose to continue our study of the high-z galaxy SMMJ02399-0136 at z=2.8 by observing with Herschel several bright far-IR fine-structure lines from O, N, and C, as well as its rest-frame mid- and far-IR continuum. This source is an excellent target of study because it has been extensively observed in other wavelengths, we have previously detected it in the [NII] 122 and [OIII] 88 micron lines, using ZEUS on the CSO, and it resides in the epoch of peak star formation in the Universe. Furthermore, SMMJ02399 is a multi-component system with AGN and starburst components at different relative velocities. Thus it presents the unique opportunity of observing an AGN, a starburst, and their interaction simultaneously from a source at high-z. The sensitivity, resolution, and broad spectral coverage of Herschel’s spectrometers, makes Herschel the ideal observatory from which we can make these observations. For several lines, it is the only observatory capable. Our proposed Herschel observations will allow us to determine the AGN and starburst contribution to the lines, characterize the starburst and the narrow-line region of the AGN, and explore the relationships between star formation and AGN in galaxies in the early universe.

We are conducting a survey of the [CII] 158um line from galaxies at redshifts 1-2 using our grating spectrometer, ZEUS on the CSO. Our first 13 galaxy survey showed that luminous star forming galaxies in this epoch have moderate intensity kpc-scale star formation – likely an extension of the Schmidt-Kennicutt law to very high gas mass fractions. Our AGN dominated systems have similarly large scale, but significantly more intense star formation suggesting punctuated, collision-induced star formation. We were awarded OT1 PACS spectroscopy and PACS/SPIRE photometry of these sources to observe the oxygen [OI], [OIII], and [OIV] fine-structure lines and far-IR continuum to characterize the star formation and AGN activity in these sources. Only two of our sources have been observed to date, but with good astrophysical success. Since the OT1 submission, we have detected 11 more z ~1-2 sources in [CII] with ZEUS. Here we propose an OT2 oxygen line/far-IR continuum study for 10 of these new sources. The new source list significantly enhances our OT1 survey in that (1) we nearly double our sample greatly increasing statistical significance of the results (2) the new group includes 7 Spitzer/PAH sources. PAH emission arises from PDRs tracing the photo-electric heating, while the [CII] and [OI] lines trace the cooling. PAHS therefore trace star formation and, since the features are extremely bright, are excellent redshift indicators. Future missions (e.g. JWST and SPICA/SAFARI) will rely on PAH spectroscopy at high z. It is therefore vital to study PAH emission and its relationship to star formation. The proposed work explores this connection at redshifts 1-2, near the peak of star formation per unit co-moving volume over cosmic time. In this interval ZEUS and PACs share a great synergy with well-matched sensitivities enabling detections of [CII] and oxygen in a wide variety of systems.

We propose to observe with PACS and SPIRE the unique system of Abell 85: a rich cluster with a feeding filament detected in the X-ray. Through extensive optical spectroscopy, we already detected an overdensity of star-forming galaxies along the filament. Infrared observations, in conjuction with newly obtained GALEX data, will allow us to obtain a complete census of the obscured and unobscured star forming activity along the filament and inside the cluster. Since galaxies are infalling onto the cluster along the filament, this corresponds to studying the different stages of evolution of galaxies during the infall. Moreover, due to the vicinity of the cluster (z=0.055), we will obtain images deep enough to detect dwarf galaxies, those most affected by the environment for which we expect the largest variations in specific star formation.

We propose a deep and wide PACS 100 and 160micron survey of the Extended Groth Strip (EGS) region, providing an area/depth combination that is unique to Herschel deep fields and leveraging the excellent existing multiwavelength database for this field from AEGIS, CANDELS, Fidel, GTC, IRAM PdB, and other projects. With unprecedented statistics, our observations will probe `calorimetric' star formation rates based on the rest frame far-infrared SED peak, down to galaxies on the z~1 main sequence. We will characterise scalings between star formation rate, stellar mass, gas mass, dynamical mass, morphology, metallicity of typical z~1 galaxies. EGS is unrivaled for study of the effects of galaxy environment. The deep Herschel data in combination with the unique Chandra coverage for a field of this size will permit to study star formation in AGN hosts in a luminosity and redshift regime where previous results give tantalising evidence for a transition between secularly evolving hosts and more violent short term effects, but where previous Herschel datasets are limited in either statistics or depth. Beyond these two core science questions, the combination of the new Herschel data, with an estimated 3000-4000 sources, and the rich EGS multiwavelength database will permit a broad range of legacy galaxy evolution studies and provide a lasting archival value.

Imaging surveys have identified and counted a major population of very bright, massive, dusty galaxies at high redshifts. To understand the astrophysics of this population, i.e., how they generate their luminosities, requires Herschel spectroscopy of their strong diagnostic FIR fine-structure emission lines. The very large sky area surveyed by SPT provides a unique sample of such galaxies at z=2.5-6, i.e., viewed when the Universe was only 1-2 Gyrs old. They are especially bright, and therefore suitable for spectroscopy, because gravitational lensing has magnified them by 10-30 times. We propose a 2-pronged program of PACS and SPIRE spectroscopy to measure the full range of ISM ionizations, from OI, to OIII and in some cases OIV, in 17 dusty, young galaxies. The resulting line ratios will provide the first quantitative estimates of the emission from star formation, PDRs, and a possible AGN, independent of absorption. (In some galaxies, our proposed spectroscopy may be sensitive enough to detect OH lines in either absorption or emission).

We propose to conduct a survey of the host galaxies of dark gamma-ray bursts (GRBs), events whose optical afterglow flux was severely diminshed by dust within their host galaxy (and which historically have been significantly under-represented in host catalogs). Our multi-year campaign of ground- and space-based follow-up has shown that these galaxies are much redder, more luminous, and generally more diverse than ordinary GRB host galaxies, making them promising candidates for long-wavelenength follow-up. Ground-based searches for radio and submillimeter emission have so far been fruitless - yet if GRBs are indeed representative of the sites of high-redshift star-formation, large far-IR luminosities are expected for some GRB hosts. By observing at the dust emission peak, PACS is particularly sensitive to dust reradiation and is relatively unaffected by variations in dust temperature, making it ideal for finding and characterizing this elusive emission. Our PACS observations will measure or tightly constrain the far-IR luminosity and dust temperatures of many dark GRB hosts and thereby calculate the total star-formation rate and obscuration fraction of this sample. These observations, combined with our large ground- and space-based optical/NIR/MIR observing programs, will definitively reveal to what extent the obscuration properties and bolometric luminosities of dark GRB hosts resemble those of ordinary GRB hosts and of star-forming galaxy populations generally, and evaluate in detail the use of GRBs as high-z star-formation tracers. Our sample has been carefully chosen to ensure all targets are heavily dust-obscured GRBs (and not simply underluminous or poorly-observed); to represent the full range of diversity seen among dark GRB host galaxies; to have excellent existing multiwavelength follow-up with other instruments; and to optimize the detectability of the sample to Herschel, even in the pessimistic case that GRB hosts harbor little highly dust-embedded star formation.

In our deep, "blind" wide-band millimeter spectroscopic follow-up campaign on HerMES Herschel/SPIRE sources, we have recently made a spectacular discovery. Based on the secure identification of a suite of atomic fine structure and molecular lines, we have discovered Herschel's "first-born" starburst, a submillimeter galaxy at an unprecedented redshift of z=6.34, when the Universe was only 885 million years old. This source, dubbed FLS3, has a 250um to 20cm spectral energy distribution (SED) comparable to lower redshift starbursts (in the rest frame). However, due to its extreme redshift, the blue wing of the SED below 250um (rest-frame 34um) is only poorly constrained. This prevents investigations of the potential presence of warm, >100K dust associated with a dust-enshrouded, optically faint active galactic nucleus (AGN), for which there may be tentative evidence in the extensive, panchromatic dataset we were able to assemble on this source over the past three months. PACS photometry is perfectly suited to remedy this unfortunate gap in our wavelength coverage, as it covers the rest-frame 8-29um range - ideal to investigate the presence of warm dust associated with an obscured AGN. The proposed, inexpensive study (only 3.9hr of PACS photometry) will offer us a first glimpse into the science that SPICA will enable in the very early Universe at the end of this decade.

For deep imaging longward of 100 um, confusion noise sets the fundamental sensitivity limits achievable with Herschel, and these limits cannot be improved by integrating longer. To penetrate through this confusion limit and detect faint high-redshift galaxies, gravitational lensing by massive galaxy clusters offers a very powerful and yet cheap solution. For this reason, our team has been conducting a PACS/SPIRE imaging survey of 44 massive lensing clusters as one of the Herschel Key Programs, "The Herschel Lensing Survey" (PI: Egami, 292.3 hrs). Deep PACS/SPIRE imaging data of massive clusters are quite rich with a variety of information, which allows us to study not only the properties of gravitationally lensed high-redshift galaxies but also those of cluster member galaxies and the intracluster medium through the analysis of the Sunyaev-Zel'dovich effect.

In January 2010, a massive HST program targeting powerful lensing clusters was accepted as one of the three multi-cycle treasury (MCT) programs. This program, ``the Cluster Lensing And Supernova survey with Hubble'' (CLASH), has an allocation of 524 orbits, and will obtain deep ACS and WFC3 images of 25 massive galaxy clusters using 16 broad-band filters from near-UV (2250 A) to near-IR (1.6 um). These extensive multi-filter imaging observations will produce high-precision photometric redshifts (sigma/(1+z)<0.02). On average, the program spends 20 orbits per cluster. Considering this enormous investment of HST time, the CLASH program will define the ultimate sample of massive galaxy clusters on which future studies will focus.

Here, we propose to obtain deep PACS and SPIRE images for 10 CLASH clusters that still lack such data (the other 15 clusters already have a good Herschel coverage). To fully exploit the combination of the Herschel and HST data, the HLS and CLASH teams are submitting this proposal jointly with the participation of key scientists from both teams.

On the extragalactic side, one of the most remarkable results coming out of Herschel is the discovery of extremely bright (>100 mJy in the SPIRE bands) gravitationally lensed galaxies. The great sensitivity and mapping speed of SPIRE have enabled us to find these rare extraordinary objects. What is truly exciting about these bright lensed galaxies is that they enable a variety of detailed multi-wavelength follow-up observations, shedding new light on the physical properties of these high-redshift sources. In this regard, our OT1 program, "SPIRE Snapshot Survey of Massive Galaxy Clusters" turned out to be a great success. After imaging ~50 galaxies out of 279 in the program, we have already found two spectacularly bright lensed galaxies, one of which is at a redshift of 4.69. This type of cluster-lensed sources are not only bright but also spatially stretched over a large scale, so ALMA (or NOEMA in the north) is likely to be able to study them at the level of individual GMCs. Such studies will open up a new frontier in the study of high-redshift galaxies.

Here, we propose to extend this highly efficient and effective survey of gravitationally lensed galaxies to another 353 clusters carefully chosen from the SPT and CODEX cluster samples. These samples contain newly discovered high-redshift (z>0.3) massive (>3-4e14 Msun) clusters, which can be used as powerful gravitational lenses to magnify sources at high redshift. With the OT1 and OT2 surveys together, we expect to find ~20 highly magnified SPIRE sources with exceptional brightnesses (assuming a discovery rate of ~1/30). Such a unique sample of extraordinary objects will enable a variety of follow-up sciences, and will therefore remain as a great legacy of the Herschel mission for years to come.

A unique MIR/FIR signature of quenched star formation (SF) in early-type cluster galaxies has recently been discovered. This demise of active SF apparently imprints itself on the MIR (powered by SF) and FIR (powered in part by ISM radiation field) dust emission for a period of only ~few x 10^7yr. If true, this signature could be used as a marker of quenching SF and the location, hence mechanism(s) used to extinguish that final SF episode in cluster S0s, be determined. However, without FIR data it is unclear if this signature is from the lack of SF or unusually cold dust.

Our ongoing study of Abell 1882, a coalescing supergroup observed just prior to collapsing into a rich cluster, has uncovered a significant population of these galaxies. We request Herschel PACS and SPIRE observations of the supergroup Abell 1882 to validate the report of a unique MIR/FIR signature of star-formation quenching that is occurring in early-type galaxies. This 27.8hr Herschel proposal will add key knowledge to the formation process of S0 galaxies and for the member population as a whole, dust properties plus gas consumption time-scale in a supergroup in the act of forming a rich cluster.

We have discovered extreme velocity [CII] 158 um line emission from the z = 1.2 hyper-luminous QSO PG 1206+459. The [CII] line emission is concentrated in twin lobes of emission roughly centered on the CO emission but displaced +/- 1500 km/s with respect to the CO line core. The mass traced in the [CII] line is quite large - about 5E9 M(solar) in each lobe – or 13% of the total molecular gas mass in the host galaxy. We interpret this symmetric [CII] velocity structure as an outflow, likely driven by the AGN. The velocities of the [CII] lobes are larger than the escape velocity, so much of this material may leave the galaxy –quenching both star formation and AGN activity, and transforming it into a "red-and-dead" passive galaxy. The CO line profile also shows a broad and blueshifted component that may represent an additional molecular component to the outflow, although a merger origin is also possible. In OT1 we were awarded 2.9 hours of PACS spectroscopy (not yet scheduled) to observe the [OI] 63 um, [OIII] 52 and 88 um, and [OIV] 26 um lines from the blue component of the line. Here we ask for an additional 10.2 hours of PACS time to widen our spectral scan to enclose the newly discovered (March 2011) red lobe and significantly improve our detection limit over the entire velocity range. These observations will be used to constrain the physical conditions, ionization structure, total mass, and radiative environment of the outflowing material using extinction-free probes. Our [CII] observations of PG1206 represent the first time that massive outflows have been detected in the [CII] line - a well established tracer of photodissociated molecular gas. The proposed Herschel observations will lay the groundwork for future studies of molecular outflows using [CII] and other far-IR lines in the early universe that will soon be possible with ALMA.

We propose deep PACS 110/160 micron imaging for two of the most distant rich clusters ever discovered at z=1.6. These spectroscopically confirmed clusters are drawn from the homogeneously selected Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS), and have impressive spectroscopic coverage (a total of 26 confirmed members) and extensive multi-wavelength follow-up data (UV-MIR). This epoch marks a crucial turning point in the star formation rate-density relation: limited studies have shown that star formation shifts toward higher densities at z~1, and even peaks in a z=1.6 cluster core, albeit only a single cluster at this distance has been observed in the IR until now. Moreover, MIPS imaging has already identified nine cluster members, confirming that dust enshrouded star formation is occurring in these dense fields. We will use the PACS/MIPS data, in combination with the extensive optical spectroscopy and photometry, to characterize the nature of IR-luminous galaxies in clusters at z=1.6. We will also measure the total star formation rate in these clusters, which will be used to study the effect of environment on galaxy formation at an exciting new redshift regime.

We propose deep PACS imaging at 110/160 microns of a unique sample of ten high-redshift galaxy clusters spanning 0.87<z<1.34. These rich clusters are drawn from the homogeneously selected Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS), and have impressive spectroscopic coverage (a total of 457 confirmed members) and extensive multi-wavelength follow-up data (UV-MIR). These clusters bridge a pivotal epoch when star formation shifts toward higher densities and when substantial cluster mass is assembled. Moreover, MIPS imaging has already identified 55 cluster members, confirming that dust enshrouded star formation is occurring in these dense fields. We will use the PACS/MIPS data, in combination with the extensive optical spectroscopy and photometry, to characterize the nature of IR-luminous galaxies in clusters at z~1. We will also measure the total star formation rate in these clusters, which will be used to study the effect of environment on galaxy formation.

We propose Herschel-SPIRE imaging of a 14'x14' field (corresponding to 7.1 Mpc x 7.1 Mpc) around the recently discovered cluster CL1449+0856 at redshift z=2.07. This structure is the most distant X-ray luminous galaxy cluster known to date, traced by a strong overdensity of red compact galaxies. Up to now, we securely identified 21 cluster members and our Spitzer-MIPS 24micron observations reveal a very high degree of star-forming activity in the cluster core. With our SPIRE imaging, we aim to reveal obscured star-formation activity within and around this evolved galaxy cluster as expected around a rapidly assembling high-z halo, as already indicated by our very recently obtained APEX-LABOCA imaging. We will search for massive dusty starbursts as cluster members, identify and characterize the counterparts of LABOCA SMGs, determine SEDs and dust temperatures of our sources and compare the properties of our IR-bright cluster members with SMGs in blank fields. This project will push the study of massive dusty starbursts in established clusters to the highest possible redshifts.

The Planck mission has the unique capability of finding systematically and on the whole sky the rarest, most luminous high redshift submm sources. These can be lensed objects or proto-groups/clusters of galaxies containing many individual sources forming stars at very high rates.  Our full sample of candidates contains about 1 source per 30 sq. deg., and already 3 candidates have been confirmed as interesting high-z sources: one was found to be a proto-group at z~3, based on a SPIRE OT1 pilot project; and 2 others are z~3-4.6 sources already found in the H-ATLAS and around A773.  We now propose to use SPIRE to image a larger set of Planck sources to obtain a statistically significant sample of 70 high-z proto-groups and clusters.  This will give new insights into the early evolution of galaxies in the highest density regions, improving our understanding of the relationship between the growth of structures and star-formation, and placing constraints on the level of non-Gaussianity within the LCDM model.  This program exploits the exceptional synergy and complementarity between Planck and Herschel.

Using the WISE Preliminary Data Release mid-infrared and UKIDSS near-infrared catalogs, we have identified a sample of 0.8<z<1.5 infrared-bright galaxies with extremely large 9.7 micron silicate absorptions (~ 5 magnitudes). These highly obscured sources present a small but not well determined fraction of the whole ULIRG population, possibly representing one the earliest stages in the transition from star formation to black hole accretion domination, before the concealing gas and dust is expelled from the galaxy. From over 1200 square degrees and 1.6 million 12-micron sources, we extracted 230 extreme silicate absorbers, increasing the sample of known extreme silicate absorption sources by more than an order of magnitude from the mere handful (~5) now known. We propose to obtain 70, 100, and 160 micron PACS imaging of a sub-sample of 45 for which we have spectroscopic redshifts. This will allow us to measure and characterize the peak of the infrared emission providing total bolometric luminosities and allowing a full decomposition of the contributions of hot, warm, and cool dust within these extreme sources. We will also measure their mid-infrared continuum slope, critical for an accurate measurement of the depth of the silicate absorption feature. Combined with hot dust emission, the strength of the silicate absorption will put strong constraints on the size of emitting region.

We propose to use PACS and SPIRE in parallel mode to map about 45 sq deg of the nearby Fornax galaxy cluster. Our science objectives are mainly concerned with evolutionary processes within the cluster environment. Specifically we will derive FIR/sub-mm luminosity functions, construct complete spectral energy distributions, search for cold dust in the outskirts of galaxies and in the intra-galactic medium and consider and compared the properties early type and dwarf galaxies that are prolific within the cluster environment. The total time requested is 93.2 hours.

We propose to use this final Herschel call to obtain SPIRE 250,350,500 micron images of a sample of nearly 300 of the most luminous quasars to have ever existed in the universe. Our proposed programme samples the top decade of quasar optical luminosities, over the key redshift range 2.5 < z < 4.5, which corresponds essentially to the 1-2 Gyr epoch over which such objects are found. This regime has been neglected by current Herschel programmes, and our targets are too rare on the sky for more than a handful to be contained within the existing/planned Herschel SPIRE surveys. Via careful sample construction, including matched sub-samples of radio-loud and radio-quiet SDSS quasars, we aim to determine how dust-enshrouded star-formation activity in the host galaxies of these super-massive active black holes depends on their redshifts, and their optical/radio power. This will allow fundamental tests of the proposed linkage between galaxy and black-hole growth, and possible modes of feedback which seem to be required to shut down star formation in massive galaxies at these high redshifts. We believe it would be a major missed opportunity if Herschel is not used to assemble a legacy dataset for these, the presumed progenitors of today's most massive galaxies, especially since the data from this (relatively inexpensive) programme can ultimately be combined with comparable statistics on lower-luminosity quasars from the major SPIRE surveys such as H-ATLAS and HerMES (thus providing excellent coverage of the luminosity-redshift plane). Finally, since our quasar targets should mark some of the highest density regions in the young universe, we will explore the 12 sq arcmin sampled by Small-Map mode around each quasar to quantify the evidence for enhanced star-formation activity in the general vicinity of these quasar hosts, as anticipated if we are observing the progenitors of today's massive galaxy clusters.

We propose an experiment to investigate the evolution of the most massive galaxies that reside in the cores of massive clusters today. We aim to catch their progenitors - gas-rich, intensely starbursting galaxies - in the act of accretion onto massive halos at z~1. Our survey is unique because we will map a super-cluster environment that is in the throes of a spectacular 3-way merger, allowing us to examine the astrophysics of galaxy evolution during a key stage of the hierarchical build-up of large scale structure. Our target - RCS 2319 - is a system of three ~5x10^14 M_Sun galaxy clusters at z=0.9 separated by just 3 Mpc. RCS 2319 is the progenitor of a >10^15 M_Sun cluster, and the ideal target to examine the complex relationship between the formation of massive galaxies and the dense, dynamic environments they inhabit. We will obtain a deep map of RCS 2319 with SPIRE, covering a projected extent of 14x14 Mpc, including the full range of sub-environments from the dense cores out to the group-scale and filamentary structure in the super-cluster outskirts. Our goals are to (i) identify ULIRG-class (>10^12 L_Sun) cluster members and investigate their properties in the context of the super-cluster environment; and (ii) calculate the cross-power spectrum of FIR emission with galaxy surface density, allowing us to search for statistical correlations between obscured star formation and environment beyond the confusion limit.

Large-area, multi-wavelength surveys from the ground and space have discovered a new population of strongly lensed, dusty, star-forming galaxies (DSFGs). These sources have lensing magnifications of x10-50 and present an exciting new means of studying otherwise faint high-redshift contributors to the cosmic infrared background (CIB) in exquisite detail. With its large survey area and long-wavelength selection, the South Pole Telescope (SPT) selects the rarest, brightest, and most interesting sample the sample of strongly lensed DSFGs and is enabling major advances in our understanding of massive galaxy formation.

Here we request 16.9 hours of SPIRE and PACS imaging to followup a sample of 88 sources from a 1.4 mm flux-limited sample with the aim of constraining SEDs to 1) estimate photometric redshifts, 2) measure dust temperatures, 3) derive the apparent and intrinsic IR luminosities, and 4) accurately determine molecular and atomic line to luminosity ratios. This proposal is part of a systematic followup campaign which includes approved and ongoing programs with HST, VLT, Spitzer, APEX, ATCA, and ALMA early science observations.

Little is known about the redshifted FIR properties of the 1.2mm selected sample of high-redshift, dusty starburst galaxies. Constraints on the dust temperature and total FIR luminosity depend on observations at short submm-wavelengths, which are only now possible with BLAST and Herschel. We have mapped a 0.5 square degree field at 1.2mm with MAMBO, centered on the Abell 2125 cluster. Complementary deep 1.4GHz radio imaging from the VLA has allowed us to identify radio counterparts to 83% of the 1.2mm selected galaxies, making this the largest sample of starburst galaxies selected at this wavelength with robust radio counterparts. We request 5.2 hours with PACS and 2.0 hours with SPIRE to map this field over the same area covered by MAMBO. These data will provide the first constraints on the (rest-frame) FIR spectral energy distribution of such a complete sample of 1.2mm selected starbursts.

Little is currently known about the dominant mode of star-formation in high-redshift submillimeter-bright galaxies (SMGs), their relation to local ULIRGs and the contribution of AGN to their immense far-infrared (IR) luminosities. Observationally, the physical conditions in these sources are difficult to constrain because the most active regions are also the most highly obscured, and thus can only be probed with mid- and far-IR data. At high redshifts the PACS wavelength coverage is ideally suited to target critical fine structure emission lines from species including oxygen, nitrogen and silicon, and rotational transitions from molecular hydrogen. The relative fluxes of these emission lines, in combination with accurate far-IR luminosities, can be used to constrain the physical conditions in the ISM, such as the density and the ionization state, which in turn provides information about the star-formation triggers and AGN activity. However, most high-redshift galaxies are too faint for these emission lines to be detected, and therefore, studies of the high-redshift ISM are rare. We request Herschel PACS spectroscopy, and 70 and 160um photometry of 13 high-redshift (z~1 to 3), far-IR luminous, gravitationally lensed galaxies. These sources are unique -- the flux boosting from gravitational lensing means that it is feasible to observe them with Herschel, and they all have exceptional ancillary data which complements the proposed program and will maximise the science output from this project. Targets are selected from the H-ATLAS and HerMES surveys and comprise a complete sample of bright lensed SMGs with confirmed CO redshifts. The PACS photometry will constrain the far-IR SEDs, and identify any warm dust (i.e. AGN) components. The spectroscopy will be used to characterize the ISM in these sources, and will double the number of high-redshift galaxies for which such analysis is currently possible. We request a total of 78.9 hours for PACS spectroscopy (73.0 hours) and photometry (5.9 hours) of 13 sources.

Gamma-Ray Bursts (GRBs) are so luminous that they can shine through highly obscured galaxies, nearby and in the remote universe. GRBs enable identification of galaxies independently of their luminosity, thus singling out a population that is a potentially powerful probe of galaxy evolution. Here we propose PACS and SPIRE imaging of the host galaxies of dark GRBs, GRBs whose optical afterglow emission is weaker than expected relative to Xrays. Recent work suggests that the main cause of the optical darkness of a GRB is dust extinction and moderate redshift, and their hosts may be a significant component of the GRB host galaxy (GRBH) population at redshifts > 1. Our sample of 13 dark GRBHs has been carefully selected by requiring a prior Spitzer detection, so that we will be ensured of detecting the far-IR emission with Herschel. We already have collected a large amount of ancillary multiwavelength data which will be combined with the Herschel photometry to construct spectral energy distributions (SEDs) from the UV to the far-IR. Fitting SEDs with a library of galaxy templates will enable us to derive bolometric luminosities and SFRs, constrain dust mass, dust temperature, and grain properties, as well as stellar age and mass. We will compare the dust and stellar components of the galaxies, and analyze the GRBHs in the context of other high-z galaxy populations. Such a program is now possible thanks to the unique ability of Herschel to study dust emission in galaxies over a wide range of redshifts. Ultimately our proposed study of GRBHs will open a new window on the study of galaxy formation and evolution.

Understanding the nature of the most distant starburst galaxies, in particular submillimeter galaxies (SMGs), has been one of the major challenges of modern observational cosmology. However, the intrinsic faintness, heavy obscuration and large cosmological distances of these systems have precluded the characterization of their optical properties and have limited their study to the rarest starburst galaxies. The most efficient way to investigate the properties of these systems is with the aid of gravitationally lensing at IR wavelengths. The recent discovery of a bright, highly magnified (m~12) SMG, MM18423+5939 at z~4, represents an unprecedented opportunity to understand in detail the interstellar medium (ISM) conditions in these objects and to bring such studies to a new level of detail. Follow-up observations with the EVLA showed that this source forms a spectacular molecular Einstein ring in CO high-resolution images, the second such object known to date. Here, we request 29.6 hrs of Herschel/SPIRE time to simultaneously observe, for the first time, three of the main coolants of the ISM: the O[I]63um, O[III]52um and O[III]88um emission lines, in a SMG at z~4. We will obtain a direct measurement of the physical state of the dense and warm gas phase that will be directly comparable to similar observations of local galaxies. We will combine these measurements with previous CO/[CI] observations of our target to provide a critical, detailed model of its ISM gas properties namely temperatures, H2 densities, e- densities and UV radiation field. Our on-going HST/WFC3 imaging program of our target is key, since it will allow us to accurately model the lens and source-plane gas distribution for a proper interpretation of the line emission. With a total IR luminosity of 1.3x10^14/m L_sun, this source has the potential to become the archetype for future deep spectroscopy with ALMA and dense gas studies at high-redshift.

The recent detection of large amounts of molecular gas in a sample of "normal" star−forming galaxies at z~1.5 has opened up a unique window into the study of the population of galaxies that dominates the star formation rate density of the Universe. Here, we propose pioneering PACS observations of the [OI]63um emission line in the best studied sample of four such galaxies that will allow us to carry out an unprecedented characterization of their star-forming properties. We aim to characterize the warm and dense neutral gas, in combination with our CO and FIR luminosity measurements, by comparing with radiative transfer models of the interstellar medium. We will be able to study the possible relation between the [OI] line and their main physical parameters (star formation rate, star formation efficiency, masses). Herschel is the only observatory capable of performing this kind of observations, that are forbidden to ground based observatories. We request a total of 32.63h of Herschel/PACS time toprovide the last piece in the puzzle that will permit to disentangle the properties on what appear to be the progenitors of galaxies like the Milky−Way.

The deepest Herschel surveys have established a distinction between steady "main sequence" star formation, whose rate is closely tied to galaxy mass at a given redshift, and elevated starburst activity in ordinary, L*(IR) galaxies at z > 1.5. They have also shown that supermassive black hole growth occurs mainly through secular processes in these main sequence galaxies, and have revealed otherwise obscured AGN missed by the deepest X-ray surveys. However, the physical processes that trigger starbursts, and the relation between star formation, AGN activity, and the structural properties of galaxies at this peak era of galaxy growth, are far from clear. We propose a survey to address these questions by measuring far-infrared luminosities and star formation rates for a large sample of high redshift galaxies with deep, high-resolution near-infrared imaging from the CANDELS HST WFC3 Treasury program. Herschel PACS and SPIRE observations deep enough to detect 700+ L*(IR) galaxies at z > 1.5 will be obtained for the five CANDELS fields and correlated with the detailed morphological and structural properties that only HST/WFC3 imaging can provide. We will establish whether interactions and mergers drive starburst activity, and examine their relevance for fueling AGN activity. The improved statistics will allow a definitive measure of the space density of L*(IR) galaxies at z=2, a basic (and currently very uncertain) demographic quantity for the history of cosmic star formation. The survey will provide a legacy of targets for detailed investigation with ALMA, tripling (beyond GOODS-South alone) the number of ALMA-accessible fields with the deepest Herschel data.

We propose to obtain deep IR imaging at 70um, 100um, and 160um with PACS (3.4h), and PACS spectroscopy of the [C II] 158um line (3.4h) for the anomalous galaxy cluster Abell 2029. This cluster has similar properties to both cool core (low central entropy, UV emission, radio-loud) and non-cool core (no measurable cooling in X-ray, no detectable H-alpha or CO) clusters, suggesting that it may be a transition object. The presence of young stars, inferred by extended UV emission, coupled with the absence of H-alpha emission, is evidence for a recent (~10 Myr) starburst. The missing piece to this puzzle is the mid-far IR, which is the only wavelength range that has not been well studied in this system. The addition of deep mid-far IR photometry will allow us to i) confirm/disprove the presence of a young stellar population, and ii) infer a starburst age based on the dust temperature. Deep IR spectroscopy of the [C II] will probe for a hidden reservoir of cool gas and would provide an estimate of the cooling rate at lower temperatures. Combined, these observations will shed new light on a galaxy cluster that, despite its proximity and the availability of deep, multi-wavelength data, has long defied understanding.

We propose Herschel spectroscopic observations of the [C II]158 um and [O I]63 um emission lines in 4 extremely bright, lensed, high-redshift galaxies. Herschel photometric surveys conducted toward galaxy clusters have identified these highly magnified sources, which would otherwise be undetectable below the confusion limit of the instrument. These exceptional targets provide the unique opportunity to study the characteristics of the ISM in typical galaxies with moderate luminosities at high redshift.

Recent studies have identified key differences between the far-infrared properties of local LIRGS/ULIRGS and galaxies of comparable luminosity at high redshift. However, the highest redshift observations are inherently biased toward more luminous galaxies, making it difficult to extend this comparison to the abundant population which is intrinsically faint. Herschel spectroscopy of highly magnified galaxies provides the only means to probe the physical conditions within this more typical population. Measurements of the [C II] and [O I] cooling lines are sensitive to the temperature and density of the gas surrounding star−forming regions, as well as the strength of the incident far ultraviolet radiation from starbursts. These observations will provide insight into the environmental conditions that drive the differences between high-redshift star-forming galaxies and those in the local universe.

A substantial fraction of the star-formation history of the Universe is encoded in the cosmic infrared background (CIB), but fundamental issues about the sources which make up the CIB such as their redshift distribution, their stellar masses, and the masses of their host halos remain poorly constrained by current measurements.  To address these issues, we propose the Herschel Redshift Survey (HeRS), a 70 deg2 SPIRE survey in the SDSS Stripe 82.  HeRS is designed to leverage the unprecedented spectroscopic redshift and stellar mass catalogs of the Hobby Eberly Telescope Dark Energy Experiment (HETDEX) and Spitzer-HETDEX Exploratory Large Area (SHELA) Survey, in order to provide the most precise constraints yet obtained on the obscured star-formation properties of galaxies in the redshift range 1.8 < z < 3.5. HeRS will principally target two goals: i) the redshift distribution of the infrared light that makes up the cosmic infrared background; and ii) the evolution of the specific star-formation rate of galaxies as a function of redshift.  Our measurements will far outstrip any that could be made with existing or planned SPIRE surveys because the high level of confusion noise (3–30 times higher than the signal) requires cross-correlating maps with the highest quality ancillary data: specifically, data that provides extremely accurate redshifts and reliable stellar mass estimates over a wide area.  And only HETDEX spectroscopic redshifts are capable of measuring the density field and bias to the required 1–2% accuracy. These measurements will break the luminosity/redshift degeneracy plaguing the interpretation of correlation studies of the CIB, and place tight constraints on source population models. This observing cycle represents the last chance to obtain Herschel observations of what will be one of the premier cosmological fields for years to come.

We propose to measure relativistic corrections to the Sunyaev-Zel'dovich effect (rSZ) in two clusters of galaxies with SPIRE-FTS, providing measurements of the intra-cluster medium (ICM) temperature with ~30 arcsec spatial resolution. For the first time, these measurements will enable: 1) unambiguous, high significance measurement of the rSZ correction, and 2) precise determination of the temperature substructure of extremely hot clusters. Both measurements are technically feasible with SPIRE-FTS and are inaccessible in any other way. The value our proposed observations for demonstrating the ability to measure the temperature of ICM substructures in massive, complex clusters is enormous, both for cosmological applications (i.e. a precise and unbiased determination of the total mass of clusters) and for astrophysical applications (untangling the complex atmosphere of clusters using SZ). These measurements will prove that measurements of the rSZ correction can enable important new studies of cluster physics and the fleeting opportunity to make them should not be missed.

We propose PACS photometry to constrain the rest frame infrared (15-40um) properties of six 4.5<z<5.3 spectroscopically confirmed extreme starbursts (sub-mm) galaxies, tripling the sample size of well studied galaxies at z>4. This will allow us to: 1) Obtain accurate total infrared luminosity measurements for these sources resulting in an unbiased measure of star formation at z~5; 2) Determine the relative contribution of Active Galactic Nuclie (AGN) and star formation to the total infrared luminosity; 3) Characterize the amount of warm dust emission in these galaxies and compare it to their gas properties; 4) Create templates for "typical" z~5 extreme starburst (sub-mm) galaxies to inform theoretical exploration and enable photometric searches for larger samples of objects. The existing 110um and 160um PACS survey data are not deep enough to fully constrain the infrared spectral energy distributions are crucial to confirm the nature of these systems and provide tight constraints on models for dust formation in the early universe.

PACS spectroscopy of the Spiderweb radio galaxy (PKS 1138-26) at redshift z=2.156 will be used to study jet-shocked molecular and atomic gas in a rapidly evolving protocluster central galaxy. This will lead to a better understanding of the impact of AGN feedback on the evolution of massive elliptical galaxies in general. We have detected extremely luminous (7E10 Lsun) H2 0-0 S(3) emission in a deep Spitzer IRS spectroscopic map. This is by far (a factor of 50) the most luminous known molecular hydrogen emission galaxy. We estimate that there must be >1E7 Msun of warm (T=650 K) molecular gas heated by dissipation of kinetic energy from the relativistic radio jet. PACS spectroscopy of the H2 0-0 S(0) line will enable us to measure the mass of warm H2 at lower temperature (T=100-500) K, which likely constitutes the bulk of the shocked molecular gas, possibly >1E11 solar masses. We have also detected ultraluminous PAH emission indicating a star formation rate of 1000 Msun/yr. PACS spectroscopy of the [Si II] 35 micron and [O I] 63 micron cooling lines will provide additional diagnostics of the shocked neutral medium, including distinguishing between magnetic and nonmagnetic shocks, and assessing the kinematics of this important ISM component in a massive elliptical galaxy under construction.

We propose observations in the two reddest PACS and all three SPIRE bands of the host galaxies of a sample of five GRBs. The sample was carefully selected based on the detection of large extinction in the GROND SED of the GRB afterglow, and all hosts have a large amount of multiwavelength data in hand, including sensitive submm observations. Together with the Herschel data, we will model the SEDs from the UV to the submm with the broadband galaxy SED fitting software, CIGALE, to derive bolometric luminosities and SFRs, and constrain dust mass and dust temperature. We will compare the dust properties of the whole galaxy with that derived from the GRB afterglow to constrain the dust clumpiness (covering fraction, total extinction). We will also compare the dust and stellar components of the galaxies, and investigate the GRB hosts in the context of other high-z galaxies. The Herschel data will provide indispensable observations of the peak of the thermal dust emission component, which accompanied with our APEX and SCUBA submm observations will provide the most accurate measurements to date of the extinction and emission properties of dust within GRB host galaxies.

We propose Herschel PACS mapping of the central 64 square Mpc around the massive galaxy cluster MS0451 (at z=0.54) to determine the dominant physical mechanisms that trigger and quench star formation in galaxies over a wide dynamic range of local environments. MS0451 is one of the most massive, X-ray luminous clusters known, and previous studies of galaxies within the virial radius of MS0451 have found strong evidence for abrupt quenching of star formation, likely due to ram-pressure stripping by the hot intra-cluster medium (Geach et al. 2006, Moran et al. 2007). Studies focusing only on the cluster core are not sensitive to transformative effects that can begin to alter the morphology, color, and star formation rate (SFR) of galaxies on the cluster outskirts. Our observations will allow for robust measurements of star formation rates as low as ~30Msun/yr for galaxies out to ~2Rvir, and will give a more complete picture of the effect of environment on the evolution of galaxies via triggering and quenching of their star formation.

Understanding how massive black holes, galaxies and clusters of galaxies jointly emerged from inhomogeneities in the primeval Universe is one of the most compelling objectives of modern observational astrophysics. Here we propose to use SPIRE's excellent sensitivity and survey speed to obtain for the first time a significant sample of proto-clusters over the key redshift range 2 < z < 4. This would be done through imaging of fields centered at AGN selected to harbour the most massive black hole. The resulting data set will allow us to address key questions, including: (i) Are the most massive black holes at z > 2 located in the largest and most massive proto-clusters? (ii) What are the masses, sizes, total star formation rates and velocity dispersions of the protoclusters? (iii) What are the masses, ages and star formation rates of the individual proto-cluster galaxies? Do we see a spatial segregation of galaxies with different masses or star formation rates? (iv) Do the properties of the proto-clusters and their galaxies evolve with redshift? (v) Are the galaxies in these proto-clusters older, larger and more massive then field galaxies?

Herschel-GAMA: Gas-fuelling, Feedback and Star-Formation in Galaxy Groups in the Local Volume

Under the Cold Dark Matter paradigm the propensity of intergalactic baryons to cool and accrete onto existing galaxies or form new galaxies depends both on the mass of the inhabited dark matter halo through the process of virialisation, as well as on the mass, dynamical state and gas content of individual galaxies, since the latter can either enhance or hinder accretion though so-called feedback from starformation or AGN activity. We have used the unprecedented density of redshifts furnished by the Galaxy And Mass Assembly (GAMA) deep wide field spectroscopic survey to identify the first statistically significant sample of low mass groups, opening the way for deep pointed multiwavelength investigations to probe baryonic processes over a more representative population of haloes than previously possible. Here we propose deep pointed miniscan exposures with PACS at 70, 110 and 160 microns of a representative subsample of 57 low-mass blue sequence member galaxies of GAMA groups with z less than 0.04 spanning a range in dynamical mass between 10^11 and 7.10^13 M_solar and a range in galaxian stellar masses from 10^8.0 to 10^9.25, parameter space that has not yet been surveyed in the FIR. Combining this with corresponding multiwavelength data on existing blind surveys covering the GAMA footprint and deep surveys of massive clusters, we will provide a complete picture of the UV-FIR/submm emission from blue sequence galaxies spanning four orders of magnitude in host halo mass and three orders of magnitude in stellar mass. This will provide a comprehensive picture of the variation of present day SF activity with environment which will serve as a fundamental empirical constraint on the baryonic processes determining the relation of our visual perception of the Universe to its underlying DM structure.

We propose to use PACS to observe the forbidden fine-structure line [OI]63μm, and for six of the sources, the [OIII]88μm line, in a sample of 16 Herschel-SPIRE selected ULIRGs, spectroscopically confirmed at z = 1−2 (keeping [OI] in the PACS-spectrometer band). We have further chosen the sources to lie in a single southern field in order to exploit the synergy with ALMA, to provide additional line diagnostics, and to emphasize the advantage of gaining insight into an unlensed galaxy population, both from environmental effects, and to avoid the differential lensing bias which can plague line ratio diagnostics. This represents a unique sample of objects made possible only with the advent of SPIRE ULIRG selection at high−z, and importantly filling a void in existing or planned similar observations with PACS; an allocated program in OT1 (in the same field) focussed on a small sample of 870μm selected SMGs, lying mostly at z = 1.0–1.3 with a few AGN-dominated systems at z = 1.3–2.0. Our targets (which don’t overlap) will complement this sample of sources in the same cosmic volume.

We request 59.8 hours of Herschel time to observe 20 normal star-forming galaxies in the [CII] 158 micron and [OI] 63 micron lines. These galaxies lie at high redshift (1<z<3). They are highly magnified by gravitational lensing, but have modest star formation rates. Therefore they represent our best chance of studying star formation and the interstellar medium in typical, common galaxies at this epoch. Redshift 1 to 3 spans the peak of both star formation activity and black hole accretion in active galactic nuclei-- a period that was crucial in shaping our modern universe. Most of this redshift range is inaccesible to ground-based observations of [CII], [OI], or both. Herschel offers the unique opportunity to study both lines with high sensitivity throughout this epoch (using HIFI for [CII] and PACS for [OI]). These two lines are the main cooling lines of the atomic medium. By measuring their fluxes, we will measure (1) the cooling efficiency of gas, (2) gas densities and temperatures near star−forming regions, and (3) gas pressures, which are important to drive the winds that provide feedback to star−formation processes. By combining the proposed observations with existing multiwavelength data on these objects, we will obtain as complete a picture of galaxy-scale star formation and ISM physical conditions at high redshifts as we have at z=0. Then perhaps we can understand why star formation and AGN activity peaked at this epoch. In Herschel cycle OT1, 49 high redshift IR luminous galaxies were approved for spectroscopy, but only two so-called normal galaxies were included. This is an imbalance that should be corrected, to balance Herschel's legacy.

We propose to address the impact of a major merging event on star formation on the bullet-like cluster: Abell 2163. This very massive cluster, among the most luminous and hottest clusters observed in X-Ray, shows outstanding properties from X-ray to radio wavelengths. Thanks to an extensived combined Xray/optical/weak-lensing program, we have recently reconstructed the merging history of this cluster (Maurogordato et al. 2008, Bourdin et al. 2011, Okabe et al. 2011) showing definitively the occurence of a recent major merger (< 0.5 Gyr) with a fast moving gas core spatially segregated from galaxies and dark matter. Suggesting an efficient stripping of the gas core by ram pressure (Okabe et al. 2011) such a clear spatial segregation has been detected so far in very few massive clusters, the most spectacular one being 1E 0657-56, the so-called"bullet cluster". A2163, at z=0.2, is the nearest one, making it an excellent target to address in details the effect of ram pressure induced by a major merger event. Besides the "bullet" in the central region, Abell 2163 shows a filamentary complex, embedding several groups and a sub-cluster being accreted along the filament, making it also a very interesting environment to address the efficiency of galaxy pre-processing in groups and filamentary structures. We propose to perform observations of A2163 with Herschel using PACS (100 and 160 microns: 12.7h) and SPIRE (250, 350 and 500 microns: 1.3 h), requesting a total time of 14.0h. Together with extensive ancillary data on this cluster, these observations will allow us to perform good estimates of star formation rates, and recover the stellar masses and star formation histories of cluster galaxies. These will be used to test the impact of the cluster merger event and its large scale environment on star formation.

Long gamma-ray bursts (LGRBs), are the brightest transient events in the Universe. This, combined with their wide range in redshift and the fact that they are associated with the collapse of massive, low metallicity stars, establishes LGRBs as powerful probes of star formation and an unbiased method for identifying high redshift galaxies. However, due to biases in the detection of the optical emission associated with LGRBs and lack of host measurements at infrared wavelengths, it is currently unclear whether we have a representative picture of the LGRB host galaxy population. In particular, there is tentative evidence to suggest that a significant fraction of LGRB hosts are dusty and hence luminous in the infrared, an issue which can be settled uniquely with Herschel. Here we propose the first statistical study of LGRB host galaxies with Herschel/SPIRE, requesting 25 hrs of observations. Our sample of 100 LGRB host galaxies have a redshift distribution which peaks at z=2.0 and are split 50:50 into dark and bright, these classifications referring to the strength of the optical afterglow emission following the LGRB. Although, we expect a significant fraction (>20%) of the sample to be individually detected in SPIRE enabling more detailed examination of these sources, we plan to obtain a representative view of the dust properties of LGRB hosts by stacking the SPIRE images of the bright and dark sub-samples. The SPIRE bands will probe the peak of the dust emission over most of the redshift range covered by our sample, enabling us to determing average and representative measurements of the dust content, infrared luminosity, star-formation rate, dust mass/temperature and extinction for LGRB hosts. Our proposed observations are the only opportunity to compare the global dust properties of bright and dark LGRB hosts, with the results from our study having important implications in LGRB theory and LGRB progenitor models.

We propose a far-IR and submm mapping survey of the premier AKARI deep field in the North Ecliptic Pole, in PACS/SPIRE parallel mode. This is the only major deep infrared field not yet covered by Herschel guaranteed or open time key projects. The outstanding and unparalleled continuous mid-IR photometric coverage from AKARI, far better than equivalent Spitzer surveys, enables a wide range of galaxy evolution diagnostics unachievable in any other survey field (including Herschel HerMES/PEP fields), by spanning the wavelengths of redshifted PAH and silicate features and the peak energy output of AGN dust tori. The investment by AKARI in the NEP represents ~10 percent of the entire pointed observations available throughout the lifetime of AKARI. Our proposal remedies the remarkable omission from Herschel's legacy surveys of the premier extragalactic deep field from another IR space telescope.

We will simultaneously identify and find photometric redshifts for the Herschel point source population, make stacking analysis detections of the galaxies which dominate the submm extragalactic background light as a function of redshift, determine the bolometric power outputs of the galaxies that dominate the submm background, compare the UV/optical/mid-IR continuum/PAH/far-IR/submm/radio star formation rate estimator in the most comprehensive IR survey data set to date, and track the coupled stellar mass assembly and black hole accretion throughout most of the history of the Universe.

In OT1 the HOTAC concluded "The science output from the proposed survey will be outstanding [...] The panel was convinced that these observations should be done" but it since became clear that priority 2 time is very unlikely to be executed, so we request reclassification to priority 1.

We propose to detect dust associated with ram−pressure stripping through deep Herschel PACS/SPIRE imaging of a carefully chosen set of cluster galaxies that show strong signs of on−going stripping and intracluster star formation. This is a continuation of our OT1 program where we have successfully detected a dust tail caused by ram-pressure stripping in the one case where we have obtained a complete PACS/SPIRE photometer dataset. Our highest priority OT1 targets have not been observed, and our original sample was small, consisting of only five galaxies. Based on our current success, we have further refined our selection criteria to only choose galaxies within the high pressure cluster environment that show signs of intracluster star formation primarily due to ram-pressure stripping of gas. Our program will carry out deep Herschel observations of six galaxies that have highly extended (~20−80 kpc) UV and H_alpha tails associated with intracluster star formation. Herschel is the only telescope that has the sensitivity to detect the emission from dust blown out into the intracluster medium (ICM). With our proposed observations we aim to: 1. quantify the temperature, mass, and lifetime of dust blown out into (or formed in-situ within) the ICM; 2. understand the role dust plays in the existence of molecular hydrogen in the ICM and intracluster star formation. The Herschel observations will expand our already large multi−wavelength dataset and finally provide complete inventory of the gas and dust associated with ram−pressure stripping, so we can study the effects of ram−pressure on galaxy evolution. This will be the last opportunity in a very long time to make these measurements.

High redshift radio galaxies (HzRGs) are the most dramatic examples of the formation of massive galaxies in the early Universe, as evidenced by their extreme (>1000Msun/yr) star formation rates. At the same time they coincide with a phase of rapid coeval black hole (BH) growth, as revealed by their powerful active galactic nuclei (AGN). This makes HzRGs unique laboratories in which to study the coevolution of massive galaxies and their central BHs. Our team has successfully carried out comprehensive imaging surveys of 62 powerful HzRGs at z > 1 using Spitzer and Herschel. These surveys have demonstrated that HzRGs have high stellar masses (>1e11Msun), and mid-IR AGN luminosities comparable to the most powerful QSOs known. Also, they have allowed us to separate the AGN and starburst contributions to the total IR luminosity. In parallel to this, we are undertaking a large CO(1-0) line survey towards a subset of 10 HzRGs using ATCA, which will provide us with excitation-unbiased mass estimates of the total molecular gas available for star formation. With this proposal we will constrain the bulk physical conditions of the star forming gas in HzRGs using the far-infrared OI fine-structure line at 63micron, which is one of the brightest diagnostic lines of the interstellar medium (ISM) in galaxies. The [OI] line, which can contain as much as >0.1% of the total IR luminosity of a galaxy, is one of the major coolants of the ISM, and is expected to be particular bright in the type of dense, hot, star forming gas expected to dominate the ISM in HzRGs. Utilizing our accurate IR luminosity estimates and molecular gas masses in combination with [OI] we will employ photo-dissociation models to constrain the gas density and the impinging FUV radiation field. We request a total of 13.1hrs of PACS spectroscopy (~2.2hrs per source, ensuring a S/N > 5) in order to detect the [OI] line towards six carefully chosen HzRG, representative of the luminous 1 < z < 2.3 radio galaxy population.

Complete 6 band (70-500um) observations of spectroscopically-confirmed cluster members in the Bullet Cluster have revealed a galaxy population with unexpectedly warm dust (T>40K) for sub-LIRG sources. No field sources of similar luminosity, at any redshift, have comparable dust temperatures, indicating that such warm dust may at least be preferentially located in dense environments. There are currently two problems testing this hypothesis more rigorously: (1) constraining the temperature of warm dust at z~0.3, requires 70um data, as the peak moves blue-ward of the range adequately constrained by 100 and 160um alone; (2) 70um observations of massive clusters are rare, as Spitzer/MIPS was only sensitive enough to probe the nearest poor cluster environments, and Herschel programs have tended to opt for only the 100um filter configuration. Indeed, the Bullet Cluster remains one of the only massive clusters with deep 6-band Herschel photometry.

Here we propose deep 70um PACS observations of four clusters from the Herschel Lensing Survey (HLS): A68, A2744, AS1063, A851 (26.1 hours in total). This sample has the advantage of existing deep 5-band Herschel data, as well 5-band Spitzer IRAC/MIPS coverage and a wealth of optical ancillary data, including 1000s of spectroscopic redshifts. The systems cover a range of cluster morphologies (multi-component mergers to relaxed systems). The observations will allow us to: (1) constrain the characteristic dust temperature of cluster galaxies with unusually warm dust; (2) search for similarly warm dust in foreground field galaxies to assess whether the phenomenon is a product of environment; (3) better constrain the FIR luminosity for all Herschel sources, using 70um to sample the mid-IR gap between 24 and 100um, and the deeper 160um data to increase the number of SPIRE sources detected by PACS; (4) improve Herschel-based photometric redshifts for high-z lensed sources.

Gravitational lensing offers a powerful method of observing intrinsically faint, high-redshift sources. Until recently, only a handful of FIR-bright, lensed galaxies have been discovered. Most of these are magnified by a single foreground galaxy, which can be difficult to disentangle spatially. Cluster lensing, on the other hand, offers the ability to accurately reconstruct the morphology of the magnified source. The SPIRE Snapshot Survey (currently 78 clusters observed from a sample of ~280) has so far discovered 10 bright, high redshift (z>1.5) sources. These include a confirmed z=4.69 source with 4 identified optical images coincident with submm peaks, and a z=2.4 source with a 500um flux of 230 mJy. We propose PACS 100 and 160 um observations for the 10 sources (total observing time of 7.2 hours), to complete the FIR SED and enable us to accurately constrain the FIR luminosity and dust properties.

We request deep PACS imaging observations of a rare merging super-cluster, RCS2319, at z = 0.9. This system is projected to form a 10^15 MSun cluster by z = 0.2, but has been caught in the process of its assembly through the merging of three massive clusters. At this redshift star formation has migrated to higher density regions than seen locally, but it is not clear if the peak of the star-formation-rate-density relation has yet reached cluster core densities. This systems can directly answer this question by probing a wide range of galaxy environments and densities within a single uniform data set. We have assembled an extensive catalog of spectroscopy and imaging which allows us to trace the galaxy density and substructure within RCS2319 and control for galaxy mass, but lack the infrared measurements necessary for accurate star formation rates that Herschel alone can provide. With these measurements we will characterize the role of the environment in stellar mass assembly, investigate the hierarchical processes of merging and infall through which massive clusters form, and elucidate the cluster-specific mechanisms which regulate galaxy evolution within dense environments.

We propose an experiment to search for signatures of rapid growth of galaxies and AGNs in a sample of three z>2 proto-clusters. These environments are exceptionally rare, pre-virialised regions corresponding to peaks in the matter density field, located at the nodes of large-scale (>10-Mpc) filamentary structures. They are the best candidates for the progenitors of the most massive clusters of galaxies (~10^15-Msun) today. We pay special attention to an unusual class of object, preferentially located in proto-clusters: Lyman alpha blobs (LABs) - 100-kpc scale luminous emission-line gas nebulae. Some LABs show signatures of recent galaxy-galaxy mergers/interactions, are often host to luminous continuum sources, and many have evidence of gas inflows/outflows in their emission-line morphology. A significant fraction of LABs have embedded galaxies detected at X-ray, mid-infrared, and/or sub-mm wavelengths, suggesting possible rapid growths of the galaxies and AGNs in proto-cluster regions. Are the proto-cluster systems more obscured than galaxies in the field? Are the protocluster systems growing more rapidly? By mapping these proto-clusters with SPIRE, we will: (1) measure SFRs in sub-mm (rest-frame FIR) for the galaxies and AGNs in the proto-clusters, and determine how much star formation is obscured (when compared to UV estimate) and (2) determine SSFRs for the galaxies and AGNs in the proto-clusters, and see how they compare to field galaxies at z=2-3. This program will deliver fundamental information on the growth of galaxies and super-massive black holes in the densest regions of the Universe at high-redshift, and provide valuable insight into the astrophysical processes that establish the trends linking galaxy properties and their environments.