XMM-Newton-NEWS #58, 10-Jul-2006
XMM-Newton Science Operations Centre at
ESA's European Space Astronomy Centre,
P.O. Box - Apdo. 50727, 28080 Madrid, Spain
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Contents:
- Version 7.0.0 of the Science Analysis System (SAS) released
- Cross Calibration Page
- New XMM-Newton Optical Monitor Spectral Response Files (Response Matrices)
- XMM-Newton SOC URL change
Version 7.0.0 of the Science Analysis System (SAS) released
The XMM-Newton SAS team is pleased to announce the release of a new version of the Science Analysis System: SAS 7.0.0
The main changes introduced in this version with respect to the former version, SAS 6.5.0, are:
EPIC
- upgraded EPIC MOS calibration, including column dependent CTI/Gain correction, improving line widths by up to ~15%.
- improved EPIC source detection and parameterisation tasks, especially related to the detection of extended sources. Robustness and efficiency have been increased to make possible the 2XMM Catalogue derivation which is in final preparation at the time of this release.
- inclusion of PSF correction for EPIC timing and burst modes in response matrix generation.
- support for arbitrary uniform binning of MOS and PN spectra.
RGS
- introduction of a time/spectral dependent RGS effective area correction, which in particular accounts for a decrease with time of the long-wavelength sensitivity. The cross-calibration of RGS with the EPIC cameras has been considerably improved.
- flagging/discarding of RGS columns showing large Charge Transfer Inefficiency has been implemented, including the introduction of new calibration files in the system, improving small scale accuracy.
- the background calibration files have been restructured to allow the modelling of the background for spectra extracted with different selection criteria. Background models can now be generated for spectra extracted both with the new, recommended region selection in PI (95%) and with the previous default value (90%).
OM
- processing of full frame high resolution data with omichain is now more robust. Some errors due to inconsistencies in the header of the raw images have been solved.
- the structure of the final combined source list has been changed. All photometric results (count rate, magnitude, color index, flux, etc.) are given now in single columns for each source and filter instead of parameter arrays per source.
- fast mode: the time dependent sensitivity degradation correction, implemented for image mode in SAS 6.5.0 is now also available in fast mode.
- OM grism data processing: a series of small changes mainly related to improvements in the identification and extraction of the spectra and the interpretability of the data. To be consistent with these changes it has been necessary to modify the flux calibration of the UV grism. Users of SAS 7.0.0 grism data reduction must use the new OM_GRISMCAL_0004.CCF.
- For the first time, the grism processing chain includes the astrometry task omatt so that the sources of all extracted spectra (multi-object spectroscopy) are assigned astronomical coordinates. Users should be aware that this facility is still in a preliminary state and therefore the coordinates obtained may still have large errors (up to one arcmin). Note that grism astrometry requires OM_ASTROMET_0012.CCF.
All other changes were either bug fixing or better handling of calibration algorithms.
CCF
Please notice that new calibration constituent files are needed for the improvement achieved by the EPIC MOS CTI correction as well as by the RGS "cool" pixels determination and temporally-dependent effective area calculation.
The list of new CCFs follows:
- EMOS[1-2]_CTI_00[30-42].CCF containing the column dependent CTI correction factors for 13 different epochs. Please note that at the time of the SAS 7.0.0 release the calibration files are still in preparation. They will be released 2-3 weeks later. In the meantime, using the current CCF elements, SAS 7.0.0 will calculate the CTI without the column-dependent correction, as for SAS 6.5.0.
- RGS[1-2]_COOLPIX_0001.CCF contain the lists of large CTI columns, which can be discarded by applying the new rgsbadpix (and rgsproc) parameter "keepcool=no".
- RGS[1-2]_EFFAREACORR_0003.CCF with the effective area values of 5 different epochs, used for interpolation.
- RGS[1-2]_TEMPLATEBCKGND_0003.CCF containing the different template backgrounds for different selection criteria.
- OM_GRISMCAL_0004.CCF, which has to be used by the grism data processing as implemented in SAS 7.0.0.
For further details on obtaining SAS 7.0.0 please visit our SAS pages available at
http://xmm.esac.esa.int/external/xmm_sw_cal/sas.shtml
Cross Calibration Page
A new cross-calibration web page has been made available at:
http://xmm.esac.esa.int/external/xmm_sw_cal/calib/cross_cal/index.php
This page gives a summary of the cross-calibration status, both among the XMM-Newton instruments and with reference to other observatories. A report based on SAS 6.5.0 is available and will be updated on a regular basis. In addition, the web page will give some examples illustrating the very latest cross-calibration situation (currently for SAS 7.0.0) in order to provide the user with information on new important cross-calibration results between releases of the cross-calibration document.
New XMM-Newton Optical Monitor Spectral Response Files (Response Matrices)
Early in 2005 a set of OM spectral response matrices was released. They gave a single-point conversion from filter count rate to flux, assuming that the OM filter transmission was flat and neglecting colour corrections.
Although the spectral dependency is very small we have produced new response files that take into account the real shape of the OM filters. In addition response matrices for the two OM grisms have been constructed, one in the visible range and another in the UV.
The complete set, as well as a concise description and guidelines for use, can be obtained from:
http://xmm.esac.esa.int/external/xmm_sw_cal/calib/om_files.shtml
These response files will allow users to make a combined spectral fitting of XMM-Newton Optical Monitor and X-ray data using packages such as XSPEC.
XMM-Newton SOC URL change
The updating of the ESAC URL has been completed and all web page addresses of the XMM-Newton SOC now start with "
http://xmm.esac.esa.int/".
Please update your links and bookmarks accordingly.
In addition, all e-mail messages issued by the XMM-Newton SOC now end with "
@sciops.esa.int".
Yours sincerely,
XMM-Newton SOC
