Community Release Note for SPIRE Calibration 4_0
The SPIRE calibration tree "spire_cal_4_0" was released in July 2010 to be compatible with HIPE v4.0.
Impact of the changes compared to the previous release (3_2)
- Astronomer receives slightly more data at the edges of the bands (out of band data is removed, so the bandEdge product defines the data that is used in the Level-1 and 2 spectra).
- The wavescale is corrected for off-axis detectors (needed for mapping observations - it means that spectral lines should now be in the correct place in spectra from all detectors).
- Flux conversion in Level-1 products now assumes an extended source for all detectors - improved consistency. Little change in absolute calibration level.
- Flux conversion now included for each jiggle position in mapping observations - combining jiggle positions to make good maps is not possible without this.
- Reference interferogram updated for each jiggle positions. Necessary to make good maps. However, still only contains the reference for one single OD - problems with temperature drift between other ODs and this cal product are not solved yet.
- Non-linearity and temperature drift coefficients updated to match better the actual voltage coverage in flight - should lead to improved calibration accuracy.
- Point source flux conversion added in a new product. This is now based on Uranus rather than Vesta - significant increase in S/N in final calibrated point source spectra.
- Beam parameters (area and equivalent FWHM) supplied to users for first time. To be used in interactive analysis.
Differences in individual products compared to the previous release
For detailed information about each product, see http://herschel.esac.esa.int/twiki/bin/view/Public/SpireCalibrationProducts.
Release Date: July 2010 (coinciding with the public release of HIPE v4.0)
- SCalSpecBandEdge: wider band edges to match release note
- SCalSpecSmecStepFactor: first correction for off axis detectors
- SCalSpecFluxConv: add jiggle dependence, extended calibration
- SCalSpecInterRef: add jiggle dependence
- SCalSpecNonLinCorr: improved voltage coverage
- SCalSpecTempDriftCorr: to match nonLinCorr update
- SCalSpecBeamParam: new product for point source flux conversion (Uranus based) and beam parameters