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: http://xmm.vilspa.esa.es/sas/7.0.0/documentation/threads/MOS_spectrum_thread.html
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All the analysis steps are performed with single SAS tasks started from the command line to explain the general method of generating spectral products and to show explicitly the usage and setting of task parameters. The users should note that the SAS metatask xmmselect allows them to interactively define source and background regions (via ds9) and to run backscale on the fly. Especially the xmmselect:Spectral Products generation method, which in addition offers an optimization of the source extraction region and which creates source and background spectra as well as related ancillary and redistribution files in one go, might in some cases be a GUI based alternative to the command line method described below. For more details on how to use xmmselect for the generation of EPIC spectra, the reader is referred to the Users' Guide to the XMM-Newton Science Analysis System.
evselect table=MOS.fits withrateset=Y rateset=rateMOS.fits \ maketimecolumn=Y timebinsize=100 makeratecolumn=Y \ expression='#XMMEA_EM && (PI>10000) && (PATTERN==0)'
dsplot table=rateMOS.fits x=TIME y=RATE
tabgtigen table=rateMOS.fits expression='RATE<=0.35' gtiset=MOSgti.fits
evselect table=MOS.fits withfilteredset=Y filteredset=MOSclean.fits \ destruct=Y keepfilteroutput=T \ expression='#XMMEA_EM && gti(MOSgti.fits,TIME) && (PI>150)'
NOTE: arfgen/rmfgen do not support spectra extracted from a region defined in RAW coordinates
evselect table=MOSclean.fits imagebinning=binSize imageset=MOSimage.fits withimageset=yes \ xcolumn=X ycolumn=Y ximagebinsize=80 yimagebinsize=80
imgdisplay withimagefile=true imagefile=MOSimage.fits
This command is equivalent to the following:
ds9 MOSimage.fits
Fig.1: ds9 main window. A circular region (green circle) has been defined using the highlighted menu.
Fig.2: selection region properties window, pop'd-up by double-clicking on the region in the main ds9 window
evselect table=MOSclean.fits withspectrumset=yes spectrumset=MOSsource_spectrum.fits \ energycolumn=PI spectralbinsize=15 withspecranges=yes specchannelmin=0 specchannelmax=11999 \ expression='#XMMEA_EM && (PATTERN<=12) && ((X,Y) IN circle(30360.5,28400.5,640))'
evselect table=MOSclean.fits withspectrumset=yes spectrumset=MOSbackground_spectrum.fits \ energycolumn=PI spectralbinsize=15 withspecranges=yes specchannelmin=0 specchannelmax=11999 \ expression='#XMMEA_EM && (PATTERN<=12) && ((X,Y) IN circle(30720.5,26360.5,640))'If you are interested in learning how to extract the background spectra from blank sky event lists, please click here.
backscale spectrumset=MOSsource_spectrum.fits badpixlocation=MOSclean.fits
backscale spectrumset=MOSbackground_spectrum.fits badpixlocation=MOSclean.fits
Currently there are two possible approaches:
a) use the SAS task rmfgen to create a redistribution matrix for your previsouly extracted spectrum:
rmfgen spectrumset=MOSsource_spectrum.fits rmfset=MOS.rmf
NOTE: This can take long (>30 min) on low-performance computers...
b) use the ready-made (canned) matrices available at the following URL: http://xmm.esac.esa.int/external/xmm_sw_cal/calib/epic_files.shtml
NOTE: arfgen reads in the pattern range from the DSS information in the spectrum dataset, and accumulates the quantum efficiency curves over those patterns, which is then combined to the other consituents of the ARF. Be aware that the entire range of allowed patterns (0-31 for the MOS) are assumed if no pattern range is found in the DSS.
arfgen spectrumset=MOSsource_spectrum.fits arfset=MOS.arf withrmfset=yes rmfset=MOS.rmf \ badpixlocation=MOSclean.fits detmaptype=psf
FTOOL: grppha: PHA filename: MOSsource_spectrum.fits
output filename: MOSsource_spectrum.grp
chkey BACKFILE MOSbackground_spectrum.fits
chkey RESPFILE MOS.rmf
chkey ANCRFILE MOS.arf
group min 25 ! as an example
exit
FTOOL: xspec: data MOSsource_spectrum.grp
[MOS_spectrum_thread.html, v 2.2] | [Last update: 24-May-2006 by Matthias Ehle] |