Status summary: Herschel was successfully launched together with Planck on 14 May 2009. Science observing started in autumn 2009, and continued until end-of-helium which took place on 29 April 2013, in DTCP#1447 after successfully performing all observing scheduled for OD#1446.

The final completion percentages are as follows: 100% for KPGT, KPOT, GT1, GT2, and OT2p1, 99.4% for OT1p1 (the remaining were "ToO-like" observations never triggered), and 98.8%/42.5%/6.3% for OT1p2+OT2p2 top/middle/bottom thirds, making 47.8% of all p2 observations.

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Herschel detects warm gas and complex chemistry towards Sgr A*. A supermassive (about 4 million solar masses) black hole lurks in the Galactic Centre, in the direction towards Sgr A*. Although it is currently "quiet", at a distance of ~8 kpc it is hundreds of times closer than any known active supermassive black hole. Herschel spectral maps of the region covering ~52-671 µm have now been obtained (Goicoechea et al. 2013), resolving emission from within 1 pc of the black hole. The emission is dominated by atomic fine structure lines and high-J CO lines, indicating hot molecular gas that may be infalling towards the black hole. Images above: an artist's illustration of the region around the Galactic Centre (left) and a spectrum towards the Galactic Centre (right). For more information and the full image captions see the ESA Herschel Space Science Portal and SciTech web releases.

Herschel has run dry! In the afternoon today (29 April 2013) Herschel ran out of helium! To declare end-of-helium (EoHe) a number of key temperature sensor upper limits had been defined, and with two of them attained, EoHe had formally been reached. Although Herschel is out of contact with the ground for 21 out of 24 hours, it chose to reach EoHe while in contact and increasing temperatures could be followed in real time during the DTCP. The cryogenic unit displayed rising temperatures in the helium tank, violating upper limit conditions on one key parameter today at 14:49:23 (UTC), with a second parameter confirming this at 15:20:01 (UTC), thus EoHe was declared. For more information see the ESA Press Release, the ESA Space Science Portal and the SciTech web releases.

Herschel links stratospheric water in Jupiter to comet SL9 impacts. In July 1994 at least 21 discernible fragments of comet Shoemaker-Levy 9 impacted on Jupiter. Water vapour observed in Jupiter by Herschel is now linked to these impacts (Cavalié et al. 2013). PACS mapping provides the water extent over the planetary disk, while HIFI provides the vertical (pressure) profile. The observed water is located high up in the stratosphere with a clear asymmetry between the hemispheres, indicating an external isolated event as the origin. Images above: Hubble (left) and near-infrared U Hawaii (middle) images of impact sites, and Herschel water extent projected onto the planetary disk (right). For more information, images, and captions see the ESA Herschel Space Science Portal and SciTech web releases.

Herschel discovers a massively star forming galaxy at z=6.34. A massively star forming galaxy designated HFLS3 has been discovered by Herschel (Riechers et al. 2013). Being just one of many in one of the HerMES blank survey fields, it was selected for follow-up observations because its SPIRE fluxes increase with wavelength, thus being potentially at high redshift. The follow-up observations have provided an unambiguous redshift of 6.34, and with an inferred star formation rate in the range 1000-5000 (depending on the adopted IMF) solar masses per year at a lookback time of over 13 Gyr, it challenges galaxy formation theories. Images above: the Hermes field (left), a multi-wavelength zoom-in (middle), and an artist's impression (right). For more information and the full image captions see the ESA Herschel Space Science Portal and SciTech web releases, as well as the Caltech, UK Herschel outreach, ICL, CNRS (in French), IAC (in Spanish), and IRAM web releases.

Subgiant star with resolved debris disk and planet. Herschel/PACS observations have spatially resolved the emission from a debris disk (Bonsor et al. 2013) around the star kappa Coronae Borealis (κ CrB). This is a K-type subgiant star, an ex A-type star that has evolved away from the main sequence to the base of the giant branch. Interestingly, κ CrB has both at least one planet and a debris disk that has thus survived the entire main sequence phase of this approximately 2.5 Gyr old star. The image above shows the debris disk at 100 µm, the star itself is not visible. For more information and the full image caption see the ESA Herschel Space Science Portal and SciTech web releases.

Massive star formation in the W3 Giant Molecular Cloud (GMC). Spectacular Herschel imaging of the W3 GMC provides new clues to how massive stars form (Rivera-Ingraham et al. 2013). For a long time the formation of massive stars (with eight solar masses or more) has presented a conundrum, as they form they make mass accretion gradually more difficult, eventually stopping further growth. Now Herschel observations hint of a way around the problem, if the formation takes place in favourable surroundings the problem can be alleviated, which is suspected to happen in W3. In the pictures above a part of the W3 GMC as imaged by Herschel in a 70, 160, and 250 µm composite. For more information and the full image captions see the ESA Herschel Space Science Portal and SciTech web releases, as well as that of U Toronto.

Herschel enables discovery of young protostars in Orion. Herschel/PACS imaging of an area in Orion, previously imaged by Spitzer, has led to a serendipitous discovery of young protostars (Stutz et al. 2013). Herschel revealed sources not present in shorter wavelength Spitzer imaging, thus cool objects. Follow-up by APEX/SABOCA 350 µm photometry has led to a list of 15 reliably identified new protostars, possibly the youngest yet observed. For more information with detailed captions and credits to the images above, see the MPIA and NASA newsreleases. The images show the reflection nebula M78 (NGC 2068) in Orion, left image left part a Spitzer/MIPS, Herschel/PACS, and APEX/SABOCA 24/160/350 µm composite and right part a Spitzer/IRAC and MIPS 24 µm composite, the right image shows some of the protostars and their locations.

Herschel targets galactic black-hole jet. Herschel has provided the first view of GX 339-4 at far-infrared wavelengths (Corbel et al. 2013). GX 339-4 is a binary system believed to harbour a >7 solar mass black hole and a low mass companion. Herschel data allows to probe the jets down to their base, where the far-infrared emission originates, allowing a better understanding of black-hole jets and of the physical processes that take place very close to a black hole. Above (left) artist's impression of the system, and (right) two epochs (25 Feb and 6 Mar 2012) at 70 µm showing strong variability. For additional information see the ESA Herschel SciTech web release.

Herschel about to run out of helium. The Herschel cryostat was filled up and superfluid helium was produced in Kourou in April 2009. A final helium top-up was done just a day before the 14 May 2009 launch. In July 2009, only two months after launch when Herschel had thermalised in space, the "In-Orbit Commissioning Review" took place. A lifetime prediction based on the thermal mathematical model and measured inflight temperatures was provided by industry. It predicted end-of-helium end of February 2013, but with an error bar of more than half a year. Since autumn 2011 we mainly rely on analysis (pioneered by the PACS ICC) of the helium temperature increase caused by the heat dumped by the PACS and SPIRE cryo-cooler recyclings to estimate the remaining amount of helium. Figures above, observed temperature increase as function of time (T101 and T102 are two different temperature sensors), and fits of helium mass estimates since since OD#090 and for the last 50 recyclings. The predictions for end-of-helium are stable (but are possibly affected by unquantified systematic errors) and indicate Herschel will run out of helium in the second half of March 2013. For additional information see the ESA Herschel Space Science Portal and SciTech web releases.

A cool Herschel discovery. The visible "surface" of the sun is called the photosphere and has a temperature of about 5800 K. In an eclipse, a red circle around the outside of the sun can sometimes be seen, this is the chromosphere, with outside it the very hot corona. The coolest layer of the sun is the lower chromosphere at around 4100 K, then temperature increases with "altitude". A similar temperature minimum has never been observed in another star. Until now! Herschel has detected the temperature minimum in sun's twin alpha Centauri A (Liseau et al. 2013). For more information see the ESA Herschel Space Science Portal web release.

Herschel, massive black holes, and star formation. The possible feedback between active galactic nucleii driven by massive black holes and intense star formation on galactic scales is the subject of a number of Herschel observing programmes. Ancillary data such as X-ray (Page et al. 2012) and radio (Barthel et al. 2012) data, numerical simulations, as well as large datasets (Harrison et al. 2012) are all important ingredients, as outlined in the ESA Herschel SciTech Black holes and star formation: a Herschel perspective web release. In the pictures above: The COSMOS field (left) and average star formation rates at given redshift bins are plotted against AGN activity in three fields (right). See also previous news releases Do active black holes quench massive star formation?, and Powerful black holes quench massive star formation, as well as Herschel observes molecular gas being swept away on galactic scales.

Taking HIFI to the limit. The Herschel heterodyne spectrometer HIFI covers the vast spectral range 480-1250 plus 1410-1910 GHz. It does this by employing 7 mixer bands (1-7) and 14 local oscillator (LO) subbands (1A, 1B, 2A, ..., 7B). However, a small frequency range in LO band 3B could not be optimised, because of a concern about the possibility of pushing too far and losing the entire band 3B in the process. Now, at a time when Herschel is approaching end of helium (which will force an end to all further observing), "purification" of the troublesome part of band 3B has been successfully performed, and the few but long awaited observations in this part of band 3B can be conducted. For more information see the SRON web release.

Heavy hydrogen in TW Hya disk enables improved mass determination. Protoplanetary disks are composed mainly of molecular hydrogen. However, their masses are usually estimated based on observations of trace constituents, such as dust or CO emission. Uncertainties in dust or CO abundances will then be amplified in the conversion to total mass, which in itself introduces additional uncertainty. Now, thanks to Herschel/PACS spectroscopy, heavy molecular hydrogen (HD) has been observed at 112 µm in the disk of TW Hya enabling a more direct and accurate mass determination (Bergin et al. 2013). Despite an (uncertain) age of order 10 Myr TW Hya still retains a massive gaseous disk, ~50 Jupiter masses or more is implied, capable of forming a planetary system. The images above show the HD spectrum (left) and an artist's impression of the TW Hya disk. For more information and the full image captions see the ESA Herschel SciTech and Space Science Portal web releases.

Betelgeuse's enigmatic circumstellar envelope and bow shock. The interaction between stellar winds and the interstellar medium can create complex bow shocks. Spectacular Herschel/PACS imaging of the environment around Betelgeuse reveals multiple arcs 6-7 arcmin away from the star itself, and the presence of a linear bar at a distance of 9 arcmin, which probably is an interstellar structure illuminated by Betelgeuse (Decin et al. 2012). See also the ESA Herschel Space Science Portal web release.

Herschel images near-earth-object Apophis. Herschel has observed the asteroid 99942 Apophis at a distance of about 0.1 AU. By performing PACS photometry Herschel has obtained the first thermal imaging of this near-earth-object. The data have enabled new determinations of the its size, up from 270 ± 60 to 325 ± 15 m, and albedo, down from 0.33 to 0.23. These measurements play a key role for the physical characterisation of Apophis, and may contribute to improving the accuracy of long-term predictions of its orbit. For more information and the full image caption see the ESA Herschel Space Science Portal web release.

Herschel spacecraft will be "parked" in heliocentric orbit. The Herschel operational large halo orbit around L2 is unstable, and thus needs regular maintenance. Consequently, after end-of-helium (expected in March 2013), the spacecraft will need to be "parked" somewhere else with no need of orbit maintenance (sometimes referred to as "disposal" or "de-orbiting"). The baseline has been to put the spacecraft in heliocentric orbit. In June 2012 an international consortium of scientists proposed to ESA to use the spacecraft to perform a controlled impact in a suitable crater near one of the lunar poles to study the impact debris, in particular volatiles. This proposal has been studied for feasibility, assessed scientifically by the ESA Advisory Structure (SSEWG and SSAC), and scoped financially. The lunar impact option is feasible, but carries an additional cost on top of that of the heliocentric orbit option. The ESA Executive has decided that the Herschel spacecraft will be "parked" indefinitely in heliocentric orbit.

Outcome of Hubble Deep Field Initiative 2012. In a Helpdesk mailing on 27 July 2012 information was provided about a new STScI initiative regarding possible future additional Hubble Deep Fields. The mailing also solicited comments and input by interested individuals/groups in the Herschel community to participate in the formulation of the science case in general, and for a possible TBD Herschel participation in particular. The outcome of the initiative has now been posted on the HST Frontier Fields webpage, with a link to the HDFI_SWGReport2012. No request for associated new Herschel DDT observations has been submitted.

Almost 800 spectroscopic redshifts obtained for HerMES galaxies. Herschel and Keck have joined forces to study the contribution of HerMES-selected galaxies to the star formation history of the universe. The 1593 targets observed by Keck I and II provided 767 spectroscopically confirmed redshifts, 731 with z<2 and 36 (~5%) with 2<z<5, with an overall peak at z~0.85. It is concluded (Casey et al. 2012a and 2012b) that these infrared-luminous galaxies contribute about half of the cosmic star formation rate density across a wide range of epochs, particularly for redshifts z up to ~2 (lookback time up to ~10 Gyr). The illustration above shows the distribution of nearly 300 galaxies from the COSMOS field as function of lookback time. For more information and the full image caption see the ESA Herschel SciTech and Space Science Portal web releases.

Massive debris disks and exo-planetary systems. Herschel observations by the DEBRIS consortium have found massive debris disks around the M3 GJ581 (Lestrade et al. 2012) and the G5V 61Vir (Wyatt et al. 2012) stars. Both are very nearby (6.4 pc and 8.5 pc, respectively) and the debris disks are resolved, the illustrations above show artist's impressions overlaid on Herschel images of GJ581 (left) and 61Vir (right). Both stars have in common that they have low-mass planets well inside debris disks with high fractional luminosities, and lack massive planets altogether. For more information and the full image captions see the ESA Herschel SciTech and Space Science Portal web releases.

"Must-Do" Programmes posted. The outcome of the "Must-Do" process has been published on the "Must-Do" Programmes webpage and circulated through a Helpdesk mailing. The first "Must-Do" observations were executed in OD#1236 (on 1 October 2012). Thanks to all the contributors!

Herschel makes first detection of water vapour in a prestellar core. The unique capabilities provided by Herschel/HIFI has enabled the detection of water vapour in the prestellar core L1544 (Caselli et al. 2012). The 557 GHz water line was observed for a total of 13.6 hr, and shows an inverse P-Cygni profile, characteristic of gravitational contraction. The total mass of water vapour in L1544, which is on the verge of collapsing, is ~2000 Earth oceans, while a much larger reservoir of about 3 million Earth ocean masses of water ice is inferred, based on chemical models. The water vapour in the dense and cold center of L1544 is produced by energetic particles colliding with molecular hydrogen producing a faint glow of ultraviolet light, illuminating icy dust mantles and liberating water molecules, maintaining water vapour at the level detected by Herschel. Figures above, (left) a three-colour Herschel/SPIRE (250, 250, and 500 µm) composite of a region of the Taurus molecular cloud with L1544 towards lower left, and (right) the water line displayed on top of the background indicating its origin. For more information see the ESA Space Science Portal web release.

Pristine olivine found in β Pictoris debris disk. Herschel has identified crystalline material in the β Pictoris debris disk that matches pristine cometary material (de Vries et al. 2012). Olivine crystallizes out of protoplanetary disk material, and can be incorporated into planetesimals and planets. The magnesium-rich 'flavour' found around β Pictoris is associated with small primitive 'unprocessed' bodies in our own solar system. The identification was made by Herschel/PACS spectroscopy of the olivine 69 µm band, whose line properties depend on both composition and temperature. Figures above show photometry and spectroscopy of β Pictoris (left), 69 µm band properties as function of temperature and composition (middle), and olivine crystals in a meteorite (right). For more information see the ESA SciTech and Space Science Portal web releases.

"Must-Do" process community involvement update. The invitation to the community to participate in the "Must-Do" process by providing suggestions has resulted in a preliminary number of 58 suggestions received. Thanks to all the contributors! For current status see Herschel Science Centre e-News #22

Herschel displays how massive stars sculpt their surroundings. The formation of massive O and B stars has a profound impact on their environment, as shown in a number of stunning Herschel images (PACS 70/160 um (blue/green), and SPIRE 250 um (red)). These mighty stars, which infuse their surroundings with powerful winds and large amounts of ionising radiation, not only contribute to the shaping of their surrounding nebula's appearance, but also have a significant impact on the star formation activity that takes place within it. In the striking image of the Carina Nebula (left) more than a hundred massive stars are present creating an intricate network of clouds that make up this cosmic nursery where thousands of stars are being formed, providing an amazing sight (Preibisch et al. 2012). For more information and full image captions see the ESA Herschel Space Science Portal and SciTech web releases. Cygnus-X (middle) is another site of massive star formation (Hennemann et al. 2012), including the Cygnus OB2 association which hosts thousands of stars, and the famous swan (right). For more information and full image captions see the ESA Herschel Space Science Portal and SciTech web releases.

"Must-Do" observations - potential important missing Herschel science? In early 2013 Herschel will run out of helium cryogen, and all observing will come to an end. After Herschel there will be no similar observing capability available for the foreseeable future. It is therefore prudent to ask the question whether - for any reason - there is even a remote possibility that observations that "must" be done by Herschel have been "missed out". An activity to identify these hypothetical observations, should they exist has now been initiated. Community involvement is invited!

Powerful black holes quench massive star formation. Combining Herschel and Chandra observations of galaxies with redshifts in the range z=1-3 in the Chandra Deep Field North (CDF-N) Page et al. (2012) have demonstrated that the most vigorous star formation is not observed around black holes with an X-ray luminosity above 10⁴⁴ ergs per second. Using Herschel/SPIRE flux as a measure of star formation rate and Chandra X-ray flux for AGN activity, it is shown that there is a correlation between the two, but for the highest X-ray fluxes the star formation is quenched. Suppression of star formation in the host galaxy of a powerful AGN is a key prediction of models in which the AGN drives an outflow expelling the interstellar medium of its host a brief period of cosmic time. In the images above: Herschel image of CDF-N with X-ray emission overlaid in blue (left), star formation rate as a function of X-ray emission (middle), and an artist's impression of galactic outflows (right). For more information and full image captions see the ESA Herschel SciTech, the UK Herschel outreach, and the NASA Herschel web releases. See also Herschel observes molecular gas being swept away on galactic scales and Do active black holes quench massive star formation?

Fomalhaut as imaged by Herschel! Fomalhaut, one of the original 'fab four' and most well-studied 'infrared excess' main-sequence stars, has been imaged by Herschel (Acke et al. 2012). The five Herschel images (covering 70 to 500 µm) resolve the system, the most prominent feature is the main belt outside of 130 AU. Dynamical modelling using a three component model with radiative-transfer tools reveals a very active system of 'fluffy' aggregates of grains, that needs to be sustained by the grinding down of the equivalent of 2000 1 km-sized comets every day. The images above from left to right show the Fomalhaut SED, the 70 µm image, and a cut through the belt along the major axis. For more information and full image captions see the ESA SciTech and Space Science Portal web releases.

A multi-wavelength view of Centaurus A. Herschel (Auld et al. 2012), XMM-Newton, and optical data on Centaurus A (NGC5128), the closest giant elliptical galaxy containing a radio-loud AGN, have been combined providing an interesting view. Above the Herschel, XMM-Newton, and combined images. For more information and full image captions see the ESA SciTech and Space Science Portal web releases, with images and a movie.

Herschel studies brown dwarf disk and companion. Herschel has obtained the first submillimetre observations of the brown dwarf 2M1207 system (Riaz et al. 2012). It is part of the TW Hya association, and consists of a ~25 M_Jup primary with a ~5 M_Jup secondary, and a disk with a few Jupiter masses. Based on their nature, the large separation between the primary and secondary, and the age of the system, it is argued that the companion cannot have formed through core accretion. Disc fragmentation is a possible formation scenario. For more information and full image caption see the ESA SciTech web release. Note: The submillimetre flux reported from the (disk around the) brown dwarf is now attributed to a source misidentification, an erratum is being published.

Herschel commencing its 'Millenium OD'! Today 7 February 2012 Herschel is commencing its 1000th Operational Day (OD), tomorrow 8 February 2012 at 13:12 UT it will be exactly 1000 days since lift-off in Kourou. The present best estimate of the remaining cryogen lifetime predicts that Herschel will be performing science observations until approximately February 2013.

Thijs de Graauw awarded AAS prize. At its 219th meeting the American Astronomical Society (AAS) awarded the 2012 Joseph Weber Award for instrumentation to Thijs de Graauw, now the Director of ALMA but until 2008 the HIFI PI. The prize was awarded for "his leadership in the construction of powerful new astronomical instruments including the Short Wavelength Spectrometer on the Infrared Space Observatory (ISO) and the Heterodyne Instrument For the Infrared (HIFI) on Herschel." In the pictures above the HIFI FPU in SRON in 2006, Thijs at the Toucan viewing site in Kourou just before the launch of Herschel, and HIFI integrated on the optical bench in July 2007.

The iconic M16 'Eagle Nebula' in new light! Herschel and XMM-Newton have teamed up to provide a new look at the M16 'Eagle Nebula' and its 'Pillars of Creation' made iconic by Hubble in 1996. In the images above from left to right we see M16 as imaged by Herschel in a 70, 160, and 250 µm composite image, as imaged by XMM-Newton, and the Herschel and XMM-Newton images combined, giving an unprecedented new view of the nebula. For more information and full image captions see the ESA SciTech and Space Science Portal web releases, as well as the BBC News and UK Herschel outreach postings.

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Last updated: Wednesday, 08-May-2013 17:25:34 CEST