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SPIRE instrument and calibration web pages

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Introduction

This page provides up-to-date information about using the SPIRE instrument: from preparing observations to reducing your data. This page also provides you with the latest calibration accuracies and known SPIRE calibration issues.

Observing with SPIRE

The most up to date information on instrument calibration and performance is given in the SPIRE Observers' Manual. This is the reference document used by all the rest of the SPIRE user guides (eg data reduction guide, cookbooks etc). Sometimes it may happen that outdated values are quoted in some of the documents. In such a case use the values given in the SPIRE Observers' Manual.

AOT release notes

Photometer  
Photometer point source mode SPIRE photometer point source release note (30 April 2010)
Photometer scan map mode SPIRE scan map release note (20 October 2009), ADDENDUM to scan map mode (2 June 2010)
Photometer small scan map mode SPIRE small scan map mode (17 March 2010)

Spectrometer  
FTS point source mode (sparse) Spectrometer point source mode release note (21 May 2010)
FTS mapping mode (intermediate, full) Spectrometer mapping mode release note (30 April 2010))
FTS bright source modes Spectrometer bright source release note (7 September 2010)

Reducing SPIRE data

Software and documentation

  • HIPE (Herschel Interactive Processing Environment): The latest User Release HCSS version that you should use for reducing SPIRE data is HIPE v9.0.0. It can be downloaded from: http://herschel.esac.esa.int/HIPE_download.shtml. This corresponds to the developer's CIB (Continuous Integration Build) HIPE 9.0 build 2974. Please note that there is a bug in the destriper task included in HIPE 9.0.0 that may affect your final map, especially if there are bright objects in the observed field: this will be fixed in the upcoming new release of HIPE!

  • We also provide access to the latest stable developer build (latest stable CIB).
    • Beware These developer builds do not undergo the same in-depth testing as the user releases do. The latest developer build can be found here.

  • SPIA: The SPIRE Photometer Interactive Analysis (SPIA) package is available as a plug-in for HIPE. SPIA provides a structured GUI based access to the more intricate parts of the scan map photometer pipeline for SPIRE without the immediate need to resort to scripts. More information can be found in the SDRG or on the SPIA web page

The SPIRE Launch Pads

  • The SPIRE Launch Pads are single sheet quick entries (like a cheat sheet) into SPIRE data reduction and providing quick references to the relevant sections in the SPIRE Data Reduction Guide. There are launch pads for Data Access, SPIRE Photometer and Spectrometer data reduction.

Document Version
SPIRE Data Launch Pad version 1.6
SPIRE Photometer Launch Pad version 1.7
SPIRE Spectrometer Launch Pad version 1.7

Photometer data reduction

The best source of information for reducing SPIRE Photometer data is the SPIRE Data Reduction Guide available through the HIPE help. This runs through the User Pipeline scripts step by step, describes several other Useful Scripts, and offers advice for specific issues that might be encountered.

  • Note that SPIRE maps are in units of Jy/beam, and are calibrated in the assumption of a point source having a spectral index equal to -1, i.e. νSν = const. To calibrate your data for other cases or convert to e.g. Jy/sr, please refer to section 5.2 of the SPIRE Observers' Manual .

  • The SPIRE Photometer filter transmission curves, also known as Relative Spectral Response Functions (RSRF) are available here. For more details, please read the .readme file in this ftp folder.

The main issues that you might find in your data are: undetected glitches, thermistor or detector jumps, and bad baseline removal.

  • Stripes in PSW, PMW and/or PLW (Level 2) maps
    • All SPIRE photometry pipelines now use the destriper by default, which improves the issue of stripes in Level 2 maps. There should be noticeable improvements in that respect with HIPE version 9. The destriper documentation can be found on the NHSC website

  • De-glitcher masks faint sources
    • For data taken in Parallel Mode in particular (sampling at 10Hz, at high speed 60"/s), the de-glitcher may flag very faint sources as glitches when it is run with standard parameters. Faint sources may have a "delta function" shape due to the low sampling rate, which looks similar to a small glitch. Try modifying the "correlation parameter" to 0.95: this will decrease the number of detected glitches - it may be better to have a limited detection rate in first level deglitching and defer to Level 2 deglitching.

  • Cooler temperature variations (Cooler Burps)
    • The SPIRE cooler is recycled after 48 hours. Between 6 to 7h after the cooler recycle ends, its temperature rises steeply and reaches the stable plateau. Observations taken during such times may exhibit stripes in the final maps. An option to correct for this effect is now available in the User Pipelines (See the SPIRE DRG for details).

  • NaN pixels present in the PSW, PMW and/or PLW (Level 2) maps
    • This effect, related to data masking or poor coverage, is more evident in single fast-scan Parallel Mode maps. To avoid NaNs, increase the pixel size (i.e., decrease the map's resolution).
    • This effect can also occur with destriped maps. In this case check if increasing the sigma parameter or switching off the Level 2 deglitcher helps.

  • WCS in 3-colour images
    • Problems with the wrong WCS in the output RGB images in all observations reduced with HIPE 8 have been fixed in HIPE 9

  • Quality flags in the quality context
    • Currently, the quality flags at the quality context inside the observation context are just meant for HSC/ICC internal evaluation of the quality of the products and not for the users. In case the data had some serious quality problem, the PI of the program has been contacted about it. Otherwise, only information in the quality summary, when available, should concern the observers.

Source Extraction and Photometry

  • The current recommended method for photometry sourceExtractorTimeline task (formerly known as the Timeline Fitter) which works on the detector timelines. The Map based algorithm sourceExtractorSussex (SUSSEXtractor) providers good results and is useful on larger maps where the sourceExtractorTimeline will be significantly slower. sourceExtractorDaophot (DAOphot) also provides a reasonable estimate of the source flux but may require an aperture correction.

Spectrometer data reduction

The best source of information for reducing SPIRE Spectrometer data is the SPIRE Data Reduction Guide available through the HIPE help. This runs through the User Pipeline scripts step by step, describes several other Useful Scripts, and offers advice for specific types of sources:

  • Faint (<10 Jy) and medium (<100 Jy) strength sources
  • Bright sources (>500 Jy)
  • Extended sources
  • Observations with few repetitions
  • H+L observations

For faint sources, the subtraction of instrument, telescope and background emission is particularly important. Optimum subtraction can be performed in several ways (read the SPIRE Data Reduction Guide for details):

  1. Subtract the Dark Sky spectrum closest to your observation (use the "Background Subtraction" script in HIPE)
  2. Subtract the spectrum of surrounding detectors (use the "Background Subtraction" script in HIPE)

Dark Sky observations are observed on every SPIRE Spectrometer OD, and are all public in the Archive.

A listing of the available Dark Sky observations can be found here.

Spectral Cube Analysis

Spectral cubes are produced by the Spectrometer pipeline for mapping observations. Some tips, suggestions and examples of spectral cube analysis for SPIRE data are provided here.

Cookbooks

Cookbooks are provided inside the SPIRE Data Reduction Guide (see above).

The standalone "Photometry Cookbook", is no longer maintained - it is being incorporated into the SPIRE DRG - please see the SDRG for photometry cookbook information, and raise a Helpdesk ticket if you find something missing.

SPIRE calibration file versions

The available calibration trees for SPIRE are listed below (with the current operational version at the top).

SPIRE Calibration Tree Applicable HIPE Version Comment
SPIRE_CAL_9_1 HIPE v9 Final v9 cal tree, currently used in operations.
SPIRE_CAL_8_1 HIPE v8 Final v8 cal tree
SPIRE_CAL_7_0 HIPE v7 Final v7 cal tree.
SPIRE_CAL_6_1 HIPE v6 Final v6 cal tree
(SPIRE_CAL_6_0) HIPE v6 Spec major update
SPIRE_CAL_5_2 HIPE v5 Final v5 cal tree
(SPIRE_CAL_5_1) HIPE v5  
(SPIRE_CAL_5_0) HIPE v5 Phot flux conv. based on Neptune. Spec major update
SPIRE_CAL_4_0 HIPE v4 Spec point source flux conv based on Uranus
SPIRE_CAL_3_2 HIPE v3  
(SPIRE_CAL_3_1) HIPE v3  
(SPIRE_CAL_3_0) HIPE v3  
SPIRE_CAL_2_1 HIPE v2 Spec point source flux conv based on Vesta
(SPIRE_CAL_2_0) HIPE v2  
SPIRE_CAL_1_2 HIPE v1 Phot flux conv based on Ceres
(SPIRE_CAL_1_1) HIPE v1 Pre-launch dummy values

More details of the changes in each version are given here.

Any of the calibration trees can be retrieved in HIPE from the HSA using (e.g.) cal = spireCal(calTree="spire_cal_9_1") etc. The default (applicable to the Hipe version) can be obtained with cal = spireCal(calTree="spire_cal") The latest calibration context for SPIRE can be obtained as a .zip file from Latest calibration trees. The zipped file is a pool, so it should be unpacked in the local store folder and then loaded in HIPE with cal = spireCal(pool="spire_cal_9_1").

See the SPIRE Data Reduction Guide for more details.

SPIRE calibration and performance

Photometer calibration

  • SPIRE Photometer Beams:
    • These are available in the SPIRE calibration context, at the standard map pixel size of (6,10,14) arcsec/pixel for (250,350,500) Ám bands, and can be accessed in HIPE after a calibration context has been loaded (see above).
    • Tip, idea The observed beams at much finer scale of 1 arcsec/pixel, as well as the theoretical ones, are available from here . Please read the release note for more details.

  • SPIRE Photometer filter transmission curves:
    • These are also available in the SPIRE calibration context (photRsrf) and can be accessed in HIPE after a calibration context has been loaded (See above).

  • Neptune and Uranus models used for the SPIRE photometer flux calibration:
    • The ESA2 models currently used in the SPIRE calibration are available here.

Spectrometer calibration

Important FTS information, including details of the calibration, point source and extended source calibration etc, is available in the SPIRE Observers' Manual, Sections 4.2 and 5.3. These two sections are a must-read for anybody processing SPIRE FTS data.

Interest groups and scripts

  • The following interest groups relate to processing of observations taken with SPIRE. The links provided allow subscription to these interest groups.
    • subscribe to the SPIRE Photometer interest group
    • subscribe to the SPIRE and PACS parallel mode large map and point source extraction interest group
    • subscribe to the SPIRE Spectrometer interest group
    • subscribe to the PACS, SPIRE and HIFI spectral maps interest group
  • User contributed scripts: Users are welcome to submit scripts and software that they believe could be of general interest to the community to the Herschel http://herschel.esac.esa.int/esupport/Helpdesk.

Further information

Contact the Helpdesk

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf Phot_Pipeline_Issue7.pdf r1 manage 453.9 K 2011-05-06 - 11:07 LucaConversi  
PDFpdf Pipe_Description_2.1.pdf r1 manage 2078.9 K 2011-05-06 - 11:06 LucaConversi  
PDFpdf SPIRE-BSS-DOC-002966_SPIRE_Spectrometer_pipeline_description_Issue_4_0_1.pdf r1 manage 793.5 K 2012-02-28 - 09:49 EdwardPolehampton  
PDFpdf SPIRE_DataLaunchPad_v1.6.pdf r1 manage 200.4 K 2012-08-24 - 13:57 ChrisPearson SPIRE Data Launch Pad v1.6
PDFpdf SPIRE_PhotometerLaunchPad_v1.7.pdf r1 manage 205.4 K 2012-08-24 - 13:58 ChrisPearson SPIRE Photometer Launch Pad v1.7
PDFpdf SPIRE_SpectrometerLaunchPad_v1.7.pdf r1 manage 190.6 K 2012-08-24 - 13:57 ChrisPearson SPIRE Spectrometer Launch Pad v1.7
PDFpdf aa14519-10.pdf r1 manage 1321.5 K 2011-01-24 - 09:51 AnthonyMarston SPIRE A&A paper, Griifin et al 2010
PDFpdf aa14605-10.pdf r1 manage 264.1 K 2011-01-24 - 16:48 IvanV SPIRE in-flight calibration
PDFpdf beam_release_note_v1-1.pdf r1 manage 4044.5 K 2011-05-11 - 09:44 LucaConversi  
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Topic revision: r67 - 2012-09-10 - IvanV
 
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