Difference: HifiCalibrationWeb (106 vs. 107)

Revision 1072017-01-09 - DavidTeyssier

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META TOPICPARENT name="WebHome"

HIFI instrument and calibration web page


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NEW NEW NEW Latest updates -- 26 September 2016 NEW NEW NEW
  • HIPE 14.2 is the latest user release
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NEW NEW NEW Latest updates -- 10 January 2017 NEW NEW NEW
  • HIPE 15.0 is the latest user release
 
  • A new HIFI calibration tree has been released, with very minor updates
  • The first version of the HIFI handbook is now available
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  • Check the important calibration updates and associated improvements expected in the HIPE 14.0.1 and upcoming 14.1 reprocessed data - this includes in particular updated sideband gain ratio in bands 1 to 4
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  • Check the important calibration updates and associated improvements expected in the HIPE 14 (and final) reprocessed data - this includes in particular updated sideband gain ratio in bands 1 to 4
 
  • The HIFI products now come with a frequency-dependent intensity calibration uncertainty budget
  • Channel flags for spurs are now populated in all HIFI observations (this was limited to spectral scan up to HIPE 13)
  • Re-organisation of the HIFI quality flags for a better assessement of issues being relevant or not to the end products
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Reducing HIFI data

Recommended User release

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HIPE 14 and Java 8 : please consult the HIPE Known Issues page regarding important information on issues with Java for different versions of HIPE.

Which data would most benefit from being reprocessed in HIPE 14.1/14.2 ?

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HIPE and Java 8 : please consult the HIPE Known Issues page regarding important information on issues with Java for different versions of HIPE.

Should I reprocess my date with HIPE 15.0 ?

 
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If your data have been processed with HIPE 14.1
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HIPE 15.0 is the final user release of HIPE. This version provides an optimisation of various interactive analysis tools offered within HIPE, however, it does not provide any change in the instrument pipeline algorithm. As such products generated with HIPE 15.0 will be identical (within negligible differences for very particular cases - see the DP known issues page) to those generated during the last bulk reprocessing, which corresponds essentially to HIPE 14.1 for HIFI products. The main new or upgraded functionalities offered by HIPE 15 are summarised in the What's New page.

Which data did most benefit from being reprocessed in HIPE 14.1/14.2 ?

 
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  • Isolated problematic processing with 14.1
    • A dozen of observations was not properly processed in 14.1 and 14.0.1. The list of those obsids is: 1342197147, 1342210032, 1342216806, 1342219255, 1342219454, 134230216, 1342245299, 1342246507, 1342245997, 1342250406, 1342250721, 1342265972, 1342263227, 1342192673, 1342218631. These observations have been reprocessed correctly with 14.2.
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If your data have been processed with HIPE 14.1
 
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  • Isolated problematic processing with 14.1
    • A dozen of observations was not properly processed in 14.1 and 14.0.1. The list of those obsids is: 1342197147, 1342210032, 1342216806, 1342219255, 1342219454, 134230216, 1342245299, 1342246507, 1342245997, 1342250406, 1342250721, 1342265972, 1342263227, 1342192673, 1342218631. These observations have been reprocessed correctly with 14.2
  If your data have been processed with HIPE 14.0.1

  • Spectra mean and median statistical numbers
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  If your data have been processed with HIPE 13.0, HIPE 12.0 or HIPE 11.1

  • Intensity calibration uncertainty
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    • HIPE 14 introduces a new product providing an estimated breakdown of the intensity calibration uncertainty. The uncertainties are given separately for each component, as well as in a quadratic sum fashion for all statistically independent elements. This sum applies to the calibration of data in the Ta* scale. Further systematic and random error apply for data converted into different intensity scales (e.g. Tmb or Jy). See further details in section 9 of the DRG.
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    • HIPE 14 introduces a new product providing an estimated breakdown of the intensity calibration uncertainty. The uncertainties are given separately for each component, as well as in a quadratic sum fashion for all statistically independent elements. This sum applies to the calibration of data in the Ta* scale. Further systematic and random error apply for data converted into different intensity scales (e.g. Tmb or Jy). See further details in section 9 of the DRG.
 
  • Pointing reconstruction
    • In HIPE 14, those observations where the interlacing mode was activated (i.e. using more than just 9 guide stars in the star tracker) will benefit from an more accurate reconstructed astrometry and so positions may change in those cases. On top of that, the quality figure associated to the new gyro-propagated method introduced back in HIPE 13 (see also the following Pointing Information page) is now computed in a slightly different fashion. Since the application or not of the gyro-propagated pointing is, for HIFI, conditional upon a certain threshold on this quality (avoiding to apply the new pointing reconstruction to under-performing case), the number of case making us of one or the other approach will differ in HIPE 14 - we recall that in case the gyro-propagated method is discarded, the pointing is the same as that used back in HIPE 12.For the HIFI data such a correction is applied in a conditional fashion depending on a quality figure computed for each individual observation. The new pointing reconstruction will not apply to under-performing cases, and those latter will still use the pointing files used back in HIPE 12. Details about the new attitude reconstruction, and the way it is approached and may impact the HIFI data, can be found in this memo.

  • Band 6 and 7 observations
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    • From HIPE 13 onward observations in bands 6 and 7 have been automatically corrected from the Electrical Standing Wave affecting those data. The correction is based on an optimised fit to the baseline artefact stored in the HIFI calibration files and applied by the pipeline. In HIPE 14, some of those stored solutions have been refined and so the resulting products will be improved. For instructions on how to benefit from this reprocessing and see the typical improvement expected in the data please refer to this section from the HIFI Data Reduction Guide (DRG).
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    • From HIPE 13 onward observations in bands 6 and 7 have been automatically corrected from the Electrical Standing Wave affecting those data. The correction is based on an optimised fit to the baseline artefact stored in the HIFI calibration files and applied by the pipeline. In HIPE 14, some of those stored solutions have been refined and so the resulting products will be improved. For instructions on how to benefit from this reprocessing and see the typical improvement expected in the data please refer to this section from the HIFI Data Reduction Guide (DRG).
 
  • Spectral Scan observations
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    • The reprocessing of spectral scans in HIPE 13 made use of optimised mask tables for spurs and unruly baseline ranges, resulting in improved deconvolved solutions at the Level 2.5 (an example of such improvement between HIPE 12 (left - red) and HIPE 13 (right - black) is shown in this plot - see also section 5.4 of the DRG). In HIPE 14, a dozen of additional spectral scans (mostly from the calibration programme) have been added to this list.In order to benefit from this update you should reprocess your data from Level 0 with the new calibration tree.
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    • The reprocessing of spectral scans in HIPE 13 made use of optimised mask tables for spurs and unruly baseline ranges, resulting in improved deconvolved solutions at the Level 2.5 (an example of such improvement between HIPE 12 (left - red) and HIPE 13 (right - black) is shown in this plot - see also section 5.4 of the DRG). In HIPE 14, a dozen of additional spectral scans (mostly from the calibration programme) have been added to this list.In order to benefit from this update you should reprocess your data from Level 0 with the new calibration tree.
 
  • Spur warning flags
    • In HIPE 14, a new channel flag has been introduced ("warning") that will be assigned to the data based on a knowledge base of spurious features built from the spectral scan flagging (see bullet above). These flags will be applied to all point and mapping observations. They should be taken as indicative as they not necessarily accurately match spurious features in the data where they got applied. For this reason, this new flag is not honoured by any of the standard interactive post-processing tasks.
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    • A bug (see here) was fixed in the calculation of SSO ephemeris positions (ra_centre/dec_centre) that led to offsets of up to ~10". This bug affected users that use cubes in a co-moving frame (including the standard Level 2.5 cubes), use the doOffset task, or make explicit use of ra_centre / dec_centre in their HIPE scripts. The offset is practically constant over a map and could, e.g., make the emission of a comet appear to be off-center when it really isn't. The fixed bug is in the Level 0 pipeline, which users cannot run easily. The issue was fixed in HIPE 11.1.
If your data have been processed with a version earlier than 10.3
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  • DBS Observations If you have data processed with < HIPE 10
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  • DBS Observations If you have data processed with < HIPE 10
 
    • A new pipeline step, mkDbsReference, calculates the differences in the chop positions in all DBS observations, and after applying the band-pass correction, stores them in a product in calibration->pipeline-out called ReferenceSpectra. This allows you to check for contamination in chop positions for all types of DBS observations.
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  • Improved pointing reconstruction for observations taken between OD 320 and 761 If you have data processed with < HIPE 9
    • The pointing information attached to the data for observations taken between OD 320 and OD761 did not use the most accurate representation of the star tracker focal length. This was done for the bulk reprocessing with HIPE 9. As a consequence, some observations will experience a shift in astrometry, that can be as high as 8 arcsec. Details about the consequences for a particular obsid, and recipes to reconstruct the improved pointing yourself can be found at http://herschel.esac.esa.int/twiki/bin/view/Public/HowToUseImprovedPointingProducts as well as in the Level 0 section of the HIFI Data Reduction Guide.
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  • Improved pointing reconstruction for observations taken between OD 320 and 761 If you have data processed with < HIPE 9
    • The pointing information attached to the data for observations taken between OD 320 and OD761 did not use the most accurate representation of the star tracker focal length. This was done for the bulk reprocessing with HIPE 9. As a consequence, some observations will experience a shift in astrometry, that can be as high as 8 arcsec. Details about the consequences for a particular obsid, and recipes to reconstruct the improved pointing yourself can be found at http://herschel.esac.esa.int/twiki/bin/view/Public/HowToUseImprovedPointingProducts as well as in the Level 0 section of the HIFI Data Reduction Guide.
 
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  • Backfilling of observational parameters If you have data processed with < HIPE 9
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  • Backfilling of observational parameters If you have data processed with < HIPE 9
 
    • From 9.1 onwards, most of the observational parameters that got optimised in HSpot will be propagated into the observation context, under a new product called HifiUplinkProduct (in the auxiliary product branch). Some of these parameters will be used in the pipeline to e.g. estimate the dimension of the cubes in the mapping and have them more representative of how the map was really obtained.
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  • Solar System Object maps If you have data processed with < HIPE 9
    • Cubes for moving targets are now created in the comoving frames in HIPE 9. In order to benefit from that, you should re-pipeline from Level 0 up to Level 2.5. Note that the hifiPipeline task should be called with the option "Aux=True". Please check the Pipeline chapter of the HIFI Data Reduction Guide for more details about how to do that.
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  • Solar System Object maps If you have data processed with < HIPE 9
    • Cubes for moving targets are now created in the comoving frames in HIPE 9. In order to benefit from that, you should re-pipeline from Level 0 up to Level 2.5. Note that the hifiPipeline task should be called with the option "Aux=True". Please check the Pipeline chapter of the HIFI Data Reduction Guide for more details about how to do that.
 
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Documentation and Cookbooks

  • The HIFI Launch Pad is intended to help you quickly off the ground with HIFI data reduction
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  • Cookbooks now exist for each HIFI observing mode
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  • The HIFI Data Reduction Guide and the HIFI AOT Observing Mode Release and Performance Notes contain information you need to know about HIFI data, regardless of the software you use for data reduction
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  • A series of useful scripts can be found following the HIPE menu Scripts -> HIFI Useful Scripts

  • If you want to know more about the details of the HIFI pipeline, you should look at the HIFI Pipeline Specification Document
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  • If you are working in HIPE, the HIFI Data Reduction Guide will be your prime resource for all things HIFI but you should also look at the Herschel Data Analysis Guide for information about general tools, such as those for viewing and manipulating spectra and spectral cubes, and for obtaining data from the archive.
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  • If you are working in HIPE, the HIFI Data Reduction Guide will be your prime resource for all things HIFI but you should also look at the Herschel Data Analysis Guide for information about general tools, such as those for viewing and manipulating spectra and spectral cubes, and for obtaining data from the archive.
 
  • The full set of online documentation for the current user release also contains detailed information about the HIFI pipeline, information about scripting in HIPE, and reference manuals for command listings. New users of HIPE are recommended to read through the Quick Start Guide and the HIPE Owner's Guide
    • You can create pdfs of each document by clicking on the pdf symbol at the top of the main page.
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  • The full set of Herschel documentation for the developer track is also available. This documentation contains revisions and updates to the documentation associated with the current User Release but you should also be aware that it may describe functionality not available in the current User Release
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Typical Data Reduction Workflow

  • Download data from the HSA. If you are downloading several observations it is better to use the tar ball.
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  • Inspect data quality. Both point spectra and spectral cubes can be viewed in the SpectrumExplorer. In addition to inspecting the quality of your Level 2 data, you should always check the Level 1 data for any bad scans. If data at Level 2 appears strange then looking at Level 1 data may provide insight to the problem, see the Data Primer chapter of the HIFI Data Reduction Guide for more information about levels of data
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  • Assess whether data should be re-pipelined.
    • Look at the section above and also at the What's New in the latest User Release to decide if you should re-pipeline.
    • Note that the ICC recommends that data processing should not be allowed to fall more than one version behind the HIPE version being used.
    • Everything you need to re-pipeline data is available in the ObservationContext, and the instructions for using the pipeline, including tips on re-pipelining using new calibration data and customising the pipeline, can be found in the Pipeline chapter of the HIFI Data Reduction Guide
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  • Flag data. A user-friendly task has been developed in order to easily flag your data: flagTool. It can be used both as a GUI (similar concept as for the fitBaseline task) or in command line
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  • Remove standing waves. Standing waves are a common problem in HIFI data, particularly in bands 3, 4, 6, and 7. The HIFI Data Reduction Guide provides some information about typical standing waves in HIFI data and describes how to remove them in HIPE using fitHifiFringe and the modified band pass technique
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  • Correct baseline drift. Baselines can be flattened by subtracted, or division in the case of real continuum. This can be done in HIPE with the fitBaseline task
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  • Fold frequency switch data. Frequency switch data is not folded in the pipeline and can be done with the doFold task.
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  • Average together H and V polarisation.
    • The noise estimates given by HSpot assume that the H and V polarisations are averaged together. This can be done in HIPE with the PolarPair task, which resamples the spectra to the same frequency scale (they are frequency calibrated with different comb measurements) and then averages them. Alternatively, you can use the Accumulate task, which allows you to specify the resampling width if you desire.
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    • Note that differences may be seen in H and V profiles, see the note on H and V positions. If you are particularly interested in the spatial structure of your source you may prefer not to average the H and V polarisations together.
    • You can also average maps taken with the H and V polarisations:
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  • Spectral manipulation. The Spectral Toolbox in HIPE allows you to perform typical spectral arithmetic tasks on spectra and spectral cubes
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  • Fit lines. The SpectrumFitterGUI, which is also a part of the Spectral Toolbox, can be used to fit line profiles.
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  • Save modified data You can save data to a pool, or store your session in order to continue working in HIPE.
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  • You may wish to export data as FITS, ASCII or use the hiClass task to export data as CLASS readable FITs files.
    • Saving as FITS
    • Saving as ASCII
    • Products readable in GILDAS/CLASS: for products processed with HIPE 12 or later, you can directly read the HCSS-generated FITS files into CLASS (more details about the FITS reader can be found in this report). For products processed with an earlier version, you should use the HiClass task to export data as CLASS readable FITS files. Notes: (1) If you import products processed in HIPE 12 or 13 some warnings will be raised about missing meta-data, but the import will proceed. (2) The FITS file from Level 2 and 2.5 observations downloaded from the HSA are gzipped files. It is recommended to test that the FITS are properly un-zipped before reading to CLASS (for example using the utility ‘fv’ (FITS Viewer) among others). (3) HSC cannot guarantee that future CLASS version will be able read the HCSS-generated FITS files.
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  • You may wish to export data as FITS, ASCII or read the data in GILDAS/CLASS.
    • Saving as FITS
    • Saving as ASCII
    • Products readable in GILDAS/CLASS: for products processed with HIPE 12 or later, you can directly read the HCSS-generated FITS files into CLASS (more details about the FITS reader can be found in this report). For products processed with an earlier version, you should use the HiClass task to export data as CLASS readable FITS files. Notes: (1) If you import products processed in HIPE 12 or 13 some warnings will be raised about missing meta-data, but the import will proceed. (2) The FITS file from Level 2 and 2.5 observations downloaded from the HSA are gzipped files. It is recommended to test that the FITS are properly un-zipped before reading to CLASS (for example using the utility ‘fv’ (FITS Viewer) among others). (3) HSC cannot guarantee that future CLASS version will be able read the HCSS-generated FITS files.
 
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Dedicated data reduction tips for Spectral Scan data

  • The data needs to be deconvolved to a single sideband solution. This can be done with the doDeconvolution task, which works with an ObservationContext.
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  • It is important to clean the data before deconvolving it: this means removing standing waves, correcting baselines, and flagging out any spurs or bad data that the pipeline missed. The calibration tree for HIPE 14 provides optimised mask tables for each spectral scan obsids so it is recommended that your make use of those, typically be reprocessing your data with HIPE 14 and this calibration file (see above).
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  • Regridding in HIPE > 9 will automatically use the comoving frame for SSOs. Considering the section above, mapping observations of SSOs will benefit from reprocessing in HIPE > 11.1.

  • You can then grid your cleaned data into a spectral cube using the doGridding task, you can also use this task to customise the cube creation to best suit your science goals.
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Dedicated data reduction tips for Strong continuum observations

  • Strong continuum sources
    • An optional step in the pipeline can be used to remove standing waves arising in the loads, this is particularly effective for strong continuum sources. A report describing the technique can be found here. Instructions for using this modified passband technique are available in the Standing Wave Removal chapter of the HIFI Data Reduction Guide:
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HIFI performance and calibration

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    • Kester et al. 2016: This paper describes the derivation of the final sideband gain ratio in use in the HIFI product calibration
 
    • Sideband ratio technical note: This note describes the general calibration problem associated with the sideband gain imbalance existing in double-sideband heterodyne systems such as HIFI, and provides some recipes and calibration tables applicable to the particular case of the HIFI mixers.
    • http://arxiv.org/abs/1404.2806: "The effect of sideband ratio on line intensity for Herschel/HIFI", Experimental Astronomy.
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    • After an extensive investigation, the HIFI ICC has introduced updated sideband gain ratio in the calibration tree. A final documentation is still in preparation but the overview of the sideband gain ratio frequency dependence in each band is illustrated in this plot.
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    • After an extensive investigation, the HIFI ICC has introduced updated sideband gain ratio in the calibration tree. A final documentation is still in preparation but the overview of the sideband gain ratio frequency dependence in each band is illustrated in this plot.
 
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  • This FTP repository of system temperature plots across the IF for each HIFI subband (updated 24 Jan 2011) inform about the variation in system temperature (sensitivity) across the HIFI intermediate frequency band at various frequencies.
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  • This repository of system temperature plots across the IF for each HIFI subband (updated 24 Jan 2011) inform about the variation in system temperature (sensitivity) across the HIFI intermediate frequency band at various frequencies.
 

Calibration error budget

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Planetary model error 5 5 5 5
Beam/aperture efficiency 1.1-1.4 1.2-1.3 1-1.1 1.2-1.3
Flux loss due to pointing** 2-4 3-7 3-4 8-18
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*Note that the "sideband gain ratio" convention used in the HIFI pipeline does not correspond to the ratio between the respective sideband gains (equal to 1 for a balanced system), but to the gain in one sideband normalised by the combined gain of the two sidebands. Consequently, perfectly-balanced sidebands will feature a sideband ratio of 0.5 (see also section 5.3.1 of the Observers' Manual, and the Intensity Calibration Framework document).
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*Note that the "sideband gain ratio" convention used in the HIFI pipeline does not correspond to the ratio between the respective sideband gains (equal to 1 for a balanced system), but to the gain in one sideband normalised by the combined gain of the two sidebands. Consequently, perfectly-balanced sidebands will feature a sideband ratio of 0.5 (see also Kester et al. 2016, and the Intensity Calibration Framework document).
 
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**For a point source (worst case scenario) - this flux loss estimates takes into account an APE of 1.2", a residual SIAM bias of order 1.5" and the fact that the H/V respective apertures are slightly offset from the middle synthetic aperture used to point the telescope (offset ranging between 3" in band 1 and 0.5" in band 7)
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**For a point source (worst case scenario) - this flux loss estimates takes into account an APE of 1.2", a residual SIAM bias of order 1.5" and the fact that the H/V respective apertures are slightly offset from the middle synthetic aperture used to point the telescope (offset ranging between 3" in band 1 and 0.5" in band 7). See also section 5.6 of the HIFI handbook.
  Frequency Calibration Accuracy
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  HIFI beam coupling efficiencies
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A revision of the HIFI beam analysis has been performed, based on a multi-epoch set of measurements on Mars. As a result, a more accurate description of the HIFI beams has been obtained, leading to some change in the beam coupling efficiencies, typically a drop. The details of the analysis and the revised coupling efficiencies are given in this release note. For the record, the first release of the HIFI beam efficiencies was described in this document (17 Nov 2010). Please note that these updates will only be featured in the HIFI calibration tree from HIPE 13 onwards.
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A revision of the HIFI beam analysis has been performed, based on a multi-epoch set of measurements on Mars. As a result, a more accurate description of the HIFI beams has been obtained, leading to some change in the beam coupling efficiencies, typically a drop. The details of the analysis and the revised coupling efficiencies are given in this release note. For the record, the first release of the HIFI beam efficiencies was described in this document (17 Nov 2010). Please note that these updates will only be featured in the HIFI calibration tree from HIPE 13 onwards.
  HIFI beam maps and Encircled Energy Fraction
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 The beam material is concatenated as a single FITS file per mixer, frequency, and polarisation. Each file has three extensions tables: one for the 2-D beam model maps (2705x2705 pixels), one for the EEF, and one for the 1-D azimuthal beam averages. Note that 2-D beam model of smaller size (201x201 pixels) will also be made available in the calibration tree (not before HIPE 13), and used in the generation of Level 2.5 cubes by the pipeline. The following page provides links to each individual file (27 Mb each). Plots of the 1-D azimuthal beam averages, and EEF for each band can be found in the Appendix B of the release note.

Access to the calibration tree:

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  • Information about what calibration is found in the HIFI ObservationContext is found in the Data Primer of the HIFI Data Reduction Guide.
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  • Information about what calibration is found in the HIFI ObservationContext is found in the Data Primer of the HIFI Data Reduction Guide.
 
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  • Information about how to find what calibration version was used on your data, how to get the latest calibration, and reprocess observations with it is found in the Pipeline chapter of the HIFI Data reduction Guide.
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  • Information about how to find what calibration version was used on your data, how to get the latest calibration, and reprocess observations with it is found in the Pipeline chapter of the HIFI Data reduction Guide.
 
  • The latest calibration tree pool can also be retrieved directly here (26 September 2016).
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  • Standing waves:
    • there are several standing waves that can affect the HIFI data at various processing levels. Their nature and impact on the HIFI calibration are described in the Standing Wave technical note and, more briefly, in the Standing Wave removal chapter of the HIFI Data Reduction Guide
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    • There are various techniques currently offered to clean these baseline distortions:
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      • Remove sine waves, or combinations of sine waves. Check the bullet about usage of the fitHifiFringe task in the data reduction section above.
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      • Remove sine waves, or combinations of sine waves. Check the bullet about usage of the fitHifiFringe task in the data reduction section above.
 
      • Electrical Standing Wave (aka Matching technique): to correct for the IF standing wave present in bands 6 and 7
        • A new task hebCorrection has been implemented in HIPE 12.0 and is being used by default by the pipeline in HIPE 13 (see also the Reducing HIFI data section above). We warn that the task does not guarantee an accurate correction in all circumstances .
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        • The task is described in the following document. The mathematical background can be found in this proceeding. Unlike the script made available in previous version of HIPE, this task is applicable to any HIFI observing mode.
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        • The task is described in the following document. The mathematical background can be found in this proceeding. Unlike the script made available in previous version of HIPE, this task is applicable to any HIFI observing mode.
 
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  • Baseline removal: imperfect ON-OFF calibration scheme can result in residual baseline distortion (not necessarily standing waves). Check the bullet about usage of the fitBaseline task in the data reduction section above.
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  • Baseline removal: imperfect ON-OFF calibration scheme can result in residual baseline distortion (not necessarily standing waves). Check the bullet about usage of the fitBaseline task in the data reduction section above.
 
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  • Spectral purity: there are places over the HIFI frequency range where the Local Oscillator does not offer a single frequency tone, so that spurious spectral line may end up in the data, and the calibration of the targeted line gets affected. A dedicated cookbook on the matter is in preparation. In the meantime, we refer to section 5.4.6 of the Observer's Manual, and to the release notes provided above.
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  • Spectral purity: in a small number of cases, there are places over the HIFI frequency range where the Local Oscillator does not offer a single frequency tone, so that spurious spectral line may end up in the data, and the calibration of the targeted line gets affected. Details are given in Section 5.3.2 of the HIFI handbook.
 
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  • Spurs: Spectral Spurs are narrow and broad spectral features due to instabilities in the Local Oscillator. Up to HIPE 12, spurs have been assigned by the pipeline in an automatic fashion. In HIPE 13, this is no longer the case and the masks are assigned based on a priori tables provided by the ICC in the calibration tree. As of now, all spectral scans benefit from such tables, but only a handful of single point and spectral mapping observations. This limitation has little impact on the top level data though since no pipeline module makes use of these masks in those modes. A list of the spurs registered up to HIPE 12 can be found in section 5.4.6 of the Observer's Manual. This table will be updated soon based on the new statistics derived from the HIPE 13 mask tables.
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  • Spurs: Spectral Spurs are narrow and broad spectral features due to instabilities in the Local Oscillator. Up to HIPE 12, spurs have been assigned by the pipeline in an automatic fashion. In HIPE 13, this is no longer the case and the masks are assigned based on a priori tables provided by the ICC in the calibration tree. As of now, all spectral scans benefit from such tables, but only a handful of single point and spectral mapping observations. This limitation has little impact on the top level data though since no pipeline module makes use of these masks in those modes. A list of the spurs registered in all spectral scans has been incorporated into the HIFI calibration tree, and is used to automatically flag data accordingly in the pipeline.
 

Interest Groups and Scripts

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  • HIPI: a library of HIFI Plug-In's has been prepared by the NHSC - check the HIPI website for more information. From HIPE 13 onwards, most of those utilities have been ported to Useful scripts (Menu Scripts > HIFI Useful Scripts)
 
  • The following interest groups relate to processing of observations taken with HIFI. The links provided allow subscription to these interest groups.
    • subscribe to PACS, SPIRE and HIFI spectral maps interest group
    • subscribe to HIFI point source and spectral scan interest group
Line: 329 to 331
 

Further Information

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-- DavidTeyssier , CarolynMcCoey, SylvieFBeaulieu and RengelMiriam - 11 April 2016 -
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-- DavidTeyssier , CarolynMcCoey, SylvieFBeaulieu and RengelMiriam - 09 January 2017 -
 
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