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Recent changes in Epic-related SAS spectral tasks Richard Saxton

Recent changes in Epic-related SAS spectral tasks Richard Saxton. SPECGROUP. A new SAS task to:. A new SAS task designed to:. Define the useful range of spectral channels Group channels according to statistical criteria Set keywords for spectral fitting programs

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Recent changes in Epic-related SAS spectral tasks Richard Saxton

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  1. Recent changes in Epic-related SAS spectral tasks Richard Saxton

  2. SPECGROUP A new SAS task to: A new SAS task designed to: • Define the useful range of spectral channels • Group channels according to statistical criteria • Set keywords for spectral fitting programs • Currently works on EPIC and RGS spectra (others ?) • Enhanced version of GRPPHA

  3. Setting bad channels Bad ranges pre-defined in XMM_SPECQUAL CCF. Screenshot Of CCF blocks specgroup spectrumset=myspec.ds setbad=CCF Or can be set explicitely: specgroup spectrumset=myspec.ds setbad=“0.0-0.4 10.0-25.0” units=KEV rmfset=epn.rmf specgroup spectrumset=myspec.ds setbad=“0-10 1100-1200” MOS, PN RGS

  4. Screenshot Of CCF blocks MOS, PN RGS

  5. Grouping options • Manually set the ranges specgroup spectrumset=myspec.ds ranges=“0-10 11-20 1100-1200” • Regular binning specgroup spectrumset=myspec.ds regbinstart=1 regbinwid=10 • Group by counts specgroup spectrumset=myspec.ds mincounts=25 • Group by signal to noise specgroup spectrumset=myspec.ds minsn=5 • Group by ratio to background specgroup spectrumset=myspec.ds backgndset=mybgd.ds minratio=3 • Combination specgroup spectrumset=myspc.ds minsn=5 ranges=“0:10 1100:1200”

  6. End bin options • Set ungrouped pixels bad: specgroup spectrumset=myspec.ds minsn=5 lastbin=setbad • Add them to the adjacent group specgroup spectrumset=myspec.ds mincounts=25 lastbin=addtogroup • Set them as an independent group specgroup spectrumset=myspec.ds minsn=5 lastbin=owngroup • Group from low or high energies specgroup spectrumset=myspec.ds minsn=4 hightolow=yes

  7. Energy resolution • Use fraction of resolution defined in CCF specgroup spectrumset=myspec.ds minsn=5 oversample=3 rmfset=mymos.rmf This ensures that any one group is at least as wide as the energy resolution at the central energy of the group divided by the oversampling factor. Energy resolution is stored in the XMM_SPECQUAL CCF: MOS PN

  8. MOS PN

  9. Keyword setting • By default the program sets the BACKFILE, ANCRFILE, RESPFILE keywords to either “NONE”or to the values given on the command line. specgroup spectrumset=myspec.ds arfset=myarf.ds rmfset=myrmf.ds will set the arf and rmf filenames as given and will set BACKFILE to NONE. • These are needed for XSPEC 12 to load the file.

  10. CAL file issues • We read the energy resolution and bad channel ranges from an XMM CCF for the MOS, PN and RGS instruments. • Task should be usable for other instruments, e.g. Chandra. There is a need for a mission-independent calibration file format !

  11. ELLIPTICAL King function • Elliptical parameterisation of the 2-d stacked PSFs. Released in SAS 10. • Parameters stored in XRTn_XPSF_010.CCF files • - King fn: core radius, slope, ellipticity • - as function of (instrument), energy, off-axis angle • Phi (azimuthal) dependence = rotation of ellipse 0° 45° 90°

  12. Producing optimum ellipse • Elliptical parameterisation of the 2-d stacked PSFs. Released in SAS 10. • 1-D PSF ‘ELLBETA’ mode – King profile (r0, alpha), ellipticity – fn(instr, E, theta) + Gaussian (FWHM, norm) – used in ARF generation/spectral fitting for elliptical regions. • Phi (azimuthal) dependence = rotation of ellipse • --------------------------------------------------------------- • eregionanalyse calculates the optimum ellipse • arfgen recognises the optimum ellipse region and calculates the encircled-energy correction using the ELLBETA model. A non-optimum ellipse uses the ‘HIGH’ accuracy PSF model. • These tasks packaged up in xmmselect “OGIP spectral products’

  13. efluxer • efluxer spectrumset=mysrc.ds arfset=mysrc.arf rrmset=mysrc.rmf backgndset=mybgd.ds fluxedset=mysrc_fluxed.ds

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