Transcript specgroup spectrumset=myspec.ds minsn=5

Recent changes in Epic-related
SAS spectral tasks
Richard Saxton
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
Setting bad channels
Bad ranges pre-defined in XMM_SPECQUAL CCF.
specgroup spectrumset=myspec.ds
setbad=CCF
Screenshot
Of
CCF blocks
MOS, PN
Or can be set explicitely:
RGS
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”
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
Screenshot
Of
CCF blocks
MOS, PN
RGS
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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”
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
PN
MOS
XMM
EPIC
SOC
PN
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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.
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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 !
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
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°
XMM
EPIC
SOC
45°
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
90°
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’
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10
efluxer
efluxer spectrumset=mysrc.ds arfset=mysrc.arf rrmset=mysrc.rmf
backgndset=mybgd.ds fluxedset=mysrc_fluxed.ds
XMM
EPIC
SOC
Richard Saxton
Background, Operations & Calibration (BOC) meeting
Madrid, 23/03/10-24/03/10