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Creation of EPIC background subtracted, exposure corrected images


Introduction

This thread describes how to create EPIC background subtracted, exposure corrected images combining data from the three instruments.

Expected Outcome

The final outcome of this thread are adaptively smoothed images in two spectral bands. In the process of creating the images full field of view and outer annulus spectral products (source and model background spectra, RMFs, and ARFs) are produced as well as count, exposure, and background count images.

SAS Tasks to be Used

Prerequisites

Useful Links

Caveats

Last Reviewed: 30 October 2014, for SAS v14.0

Last Updated: 30 October 2014





Procedure

This thread contains a step-by-step recipe to create EPIC background subtracted, exposure corrected images combining data from all three instruments.
  1. Set up your SAS environment (following the SAS Startup Thread)
  2. Create cleaned (filtered for soft proton excesses) MOS and pn (including OOT processing) event files for your observation:

     epchain
     epchain withoutoftime=true
     emchain
     pn-filter
     mos-filter

    Note that mos-filter will indicate which CCDs are operating in an anomalous mode (the line with the corresponding CCD would be marked by **** in that case. In the the example below all CCDs are fine). These CCDs should be excluded in downstream processing.

     1S003
         Limit=1.0 CCD=2 Hardness=7.556 Uncertainty=1.547
         Limit=1.0 CCD=3 Hardness=8.333 Uncertainty=2.079
         Limit=0.90 CCD=4 Hardness=3.982 Uncertainty=0.595
         Limit=1.73 CCD=5 Hardness=2.182 Uncertainty=0.240
         Limit=1.0 CCD=6 Hardness=5.741 Uncertainty=1.197
         Limit=1.0 CCD=7 Hardness=6.226 Uncertainty=1.205
     2S004
         Limit=1.0 CCD=2 Hardness=3.615 Uncertainty=0.566
         Limit=1.0 CCD=3 Hardness=5.629 Uncertainty=1.032
         Limit=1.0 CCD=4 Hardness=9.391 Uncertainty=2.060
         Limit=1.0 CCD=5 Hardness=4.460 Uncertainty=0.698
         Limit=1.0 CCD=6 Hardness=7.500 Uncertainty=1.702
         Limit=1.0 CCD=7 Hardness=6.677 Uncertainty=1.286

    mos-filter and pn-filter run the SAS task espfilt (along with a few others). The diagnostic plots created by the filtering tasks mos-filter and pn-filter should also be examined as they provide an indication of the quality of the data. These have names like mos1S003-hist.qdp, mos2S004-hist.qdp, and pnS005-hist.qdp and can be plotted using the command, for example, qdp mos1S003-hist.qdp. Note that while much of the soft proton contamination is removed, there is likely to be some residual contamination left. Figure 1 shows the light-curve screening for the MOS1 instrument.

    Figure 1: MOS1 light curve for the Abell 1795 observation. Notice the residual variation of the nominally good data which indicates the possible existence of residual soft proton contamination.

  3. Run source detection and make point-source masks. Note that in this and many tasks below the exposure ID must be explicitly noted. This is done by the prefixm, prefixp, and prefix parameters.

     cheese prefixm='1S003 2S004' prefixp=S005 scale=0.5 rate=1.0 dist=40.0 \
       clobber=0 elow=400 ehigh=72000

  4. Examine the MOS soft band images created by mos-filter to confirm that the indicated CCDs are operating in an anomalous state, or that any other CCDs are not doing so, and verify that the point-source (cheese) masks look reasonable. Sometime artifacts may occur in regions of bright diffuse emission.

    Figure 2: MOS1 (left) and MOS2 (right) images in the soft (0.2-1.0 keV) band. Note the excess counts in the upper left CCD in the MOS1 image most noticeable in the unexposed (to the sky) upper left corner. Displayed by the command: ds9 *soft* &

    Figure 3: MOS1 (left), MOS2 (middle), and pn (right) cheese masks. Displayed by the command: ds9 *cheese* &

  5. Use mos-spectra and pn-spectra to create the required intermediate spectra (for the entire region of interest as well as spectra from the individual CCDs), RMF and ARF files, and detector images for the two bands and three detectors. MOS CCDs affected by anomalous states should be deselected (this is done by the ccd# parameters). MOS1 CCD6 should be deselected if the observation took place after the meteorite damage. Currently the tasks require the path to the additional CalDB files required for XMM-ESAS (in this case, /XMM/sas/CCF/esas/). The region selection expression (region parameter) is in an input file and should be in detector coordinates. If the input file does not exist, reg.txt in this case, the default is to process the entire FOV. The input energies are in eV.

     mos-spectra prefix=1S003 caldb=/XMM/sas/CCF/esas/ region=reg.txt mask=0 \
       elow=400 ehigh=1250 ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos-spectra prefix=1S003 caldb=/XMM/sas/CCF/esas/ region=reg.txt mask=0 \
       elow=2000 ehigh=7200 ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos-spectra prefix=2S004 caldb=/XMM/sas/CCF/esas/ region=reg.txt mask=0 \
       elow=400 ehigh=1250 ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos-spectra prefix=2S004 caldb=/XMM/sas/CCF/esas/ region=reg.txt mask=0 \
       elow=2000 ehigh=7200 ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     pn-spectra prefix=S005 caldb=/XMM/sas/CCF/esas/ region=pn-reg.txt \
       mask=0 elow=400 ehigh=1250 pattern=4 quad1=1 quad2=1 quad3=1 quad4=1

     pn-spectra prefix=S005 caldb=/XMM/sas/CCF/esas/ region=pn-reg.txt \
       mask=0 elow=2000 ehigh=7200 pattern=4 quad1=1 quad2=1 quad3=1 quad4=1

  6. Use mos_back and pn_back to create the quiescent particle background (QPB) spectra and images (in detector coordinates). mos_back and pn_back create QDP plot files which shows the source and model background spectra for the observation. Any discrepancies at higher energies probably indicate residual soft proton contamination, unless there are really hard and bright sources in the field. In the case of this observation the discrepancy at high energies is consistent with soft protons as a residual contamination was already expected from the light curve histogram. The QDP files have names like mos1S005-spec.qdp. The same CCD selection must be used here as were used in mos-spectra and pn-spectra.

     mos_back prefix=1S003 caldb=/XMM/sas/CCF/esas/ diag=0 elow=400 ehigh=1250 \
       ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos_back prefix=1S003 caldb=/XMM/sas/CCF/esas/ diag=0 elow=2000 ehigh=7200 \
       ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos_back prefix=2S004 caldb=/XMM/sas/CCF/esas/ diag=0 elow=400 ehigh=1250 \
       ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos_back prefix=2S004 caldb=/XMM/sas/CCF/esas/ diag=0 elow=2000 ehigh=7200 \
       ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     pn_back prefix=S005 caldb=/XMM/sas/CCF/esas/ diag=0 elow=400 ehigh=1250 \
      quad1=1 quad2=1 quad3=1 quad4=1

     pn_back prefix=S005 caldb=/XMM/sas/CCF/esas/ diag=0 elow=2000 ehigh=7200 \
      quad1=1 quad2=1 quad3=1 quad4=1

    Figure 4: MOS1 (left) and MOS2 (right) model particle images in the soft (0.4-1.25 keV) band. The different colors for the different CCDs are an indication of the variations in their exposures (caused by CCDs operating in anomalous modes, CCD1 operating in non-full field imaging mode, and the loss of CCD6 of MOS1 to the micrometeorite strike. Displayed by the command: ds9 mos1S003-back-im-det-400-1250.fits mos2S004-back-im-det-400-1250.fits &.

    Figure 5: MOS1 source (red) and QPB (green) spectra. Displayed by the command: qdp mos1S003-spec.qdp.

  7. Use rot-im-det-sky to transform the QPB images in detector coordinates into sky coordinates.

     rot-im-det-sky prefix=1S003 mask=0 elow=400 ehigh=1250 mode=1
     rot-im-det-sky prefix=1S003 mask=0 elow=2000 ehigh=7200 mode=1
     rot-im-det-sky prefix=2S004 mask=0 elow=400 ehigh=1250 mode=1
     rot-im-det-sky prefix=2S004 mask=0 elow=2000 ehigh=7200 mode=1
     rot-im-det-sky prefix=S005 mask=0 elow=400 ehigh=1250 mode=1
     rot-im-det-sky prefix=S005 mask=0 elow=2000 ehigh=7200 mode=1

  8. For convenience, rename a few files so that they are not overwritten.

     mv mos1S003-obj.pi mos1S003-obj-full.pi
     mv mos1S003.rmf mos1S003-full.rmf
     mv mos1S003.arf mos1S003-full.arf
     mv mos1S003-back.pi mos1S003-back-full.pi
     mv mos1S003-obj-im-sp-det.fits mos1S003-sp-full.fits
     mv mos2S004-obj.pi mos2S004-obj-full.pi
     mv mos2S004.rmf mos2S004-full.rmf
     mv mos2S004.arf mos2S004-full.arf
     mv mos2S004-back.pi mos2S004-back-full.pi
     mv mos2S004-obj-im-sp-det.fits mos2S004-sp-full.fits
     mv pnS005-obj-os.pi pnS005-obj-os-full.pi
     mv pnS005-obj.pi pnS005-obj-full.pi
     mv pnS005-obj-oot.pi pnS005-obj-oot-full.pi
     mv pnS005.rmf pnS005-full.rmf
     mv pnS005.arf pnS005-full.arf
     mv pnS005-back.pi pnS005-back-full.pi
     mv pnS005-obj-im-sp-det.fits pnS005-sp-full.fits

  9. Group the spectral data in preparation for spectral fitting.

     specgroup spectrumset=mos1S003-obj-full.pi mincounts=100 rmfset=mos1S003-full.rmf \
      arfset=mos1S003-full.arf backgndset=mos1S003-back-full.pi groupedset=mos1S003-obj-full-grp.pi

     specgroup spectrumset=mos2S004-obj-full.pi mincounts=100 rmfset=mos2S004-full.rmf \
      arfset=mos2S004-full.arf backgndset=mos2S004-back-full.pi groupedset=mos2S004-obj-full-grp.pi

     specgroup spectrumset=pnS005-obj-os-full.pi mincounts=100 rmfset=pnS005-full.rmf \
      arfset=pnS005-full.arf backgndset=pnS005-back-full.pi groupedset=pnS005-obj-os-full-grp.pi

  10. Fit the spectral data to determine the soft proton contamination parameters. This is aided by getting the ROSAT All-Sky Survey (RASS) spectrum of the region from the HEASARC X-ray background tool along with the appropriate spectral response matrix (rass.pi and pspcc.rsp in this Xspec XCM file). The region selected for the RASS spectrum should be typical of the nominal background in the direction of your source. For example, the spectrum in an annulus surrounding a cluster of galaxies. The fitted model is fairly complex with components representing the cosmic diffuse X-ray background (an unabsorbed thermal component about 0.1 keV, and absorbed thermal component about 0.25 keV, and the extragalactic power law with a spectral index of 1.46), a component representing your source, Gaussian lines at 1.496 keV and 1.75 keV representing the Al Kalpha and Si Kalpha lines in the MOS, lines at 1.496 keV and near 8 keV representing the Al Kalpha and Cu lines in the pn, possible solar wind charge exchange (SWCX) lines at 0.56 and 0.65 keV, and a broken power law representing the residual soft proton contamination (MOS and pn only, fitted with a diagonal matrix supplied in the XMM-ESAS CalDB release, mos1-diag.rsp.gz, mos2-diag.rsp.gz, and pn-diag.rsp.gz). The cosmic background parameters should be linked for all spectra, your source spectrum parameters should be linked for all spectra but the normalization should be fixed at 0 for the RASS data. The SWCX parameters should be linked for all spectra but the normalization should be fixed at 0 for the RASS data. The parameters for the soft proton background should be independent except that the power law index for the two MOS detectors can be linked. The non-detector components of the fit should be scaled by the solid angle in square arc minutes (the RASS spectrum is already in these units). proton_scale finds the solid angle for the region to include in the spectral fitting.

     proton_scale caldb=/XMM/sas/CCF/esas/ mode=1 detector=1 maskfile=mos1S003-sp-full.fits \
       specfile=mos1S003-obj-full.pi

     proton_scale caldb=/XMM/sas/CCF/esas/ mode=1 detector=2 maskfile=mos2S004-sp-full.fits \
       specfile=mos2S004-obj-full.pi

     proton_scale caldb=/XMM/sas/CCF/esas/ mode=1 detector=2 maskfile=pnS005-sp-full.fits \
       specfile=pnS005-obj-full.pi

    The result of the fitting process is shown in Figure 6.

    Figure 6: Best fit of the Abell 1795 data from the full FOV. The green data and model curves are from the pn, the black and red data and model curves are from the MOS1 and MOS2, respectively, and the blue model and curve are from the RASS. The single kinked but otherwise straight line model curves for the MOS and pn are the soft proton contributions (broken power law).

  11. proton uses the fitted soft proton parameters to create images of the soft proton contamination in detector coordinates.

     proton prefix=1S003 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=0 ccd7=1 elow=400 ehigh=1250 spectrumcontrol=2 bindl=1.3388 bindh=0.9997 bnorm=0.2407

     proton prefix=1S003 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=0 ccd7=1 elow=2000 ehigh=7200 spectrumcontrol=2 bindl=1.3388 bindh=0.9997 bnorm=0.2407

     proton prefix=2S004 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=0 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=1 ccd7=1 elow=400 ehigh=1250 spectrumcontrol=2 bindl=1.3388 bindh=0.9997 bnorm=0.2160

     proton prefix=2S004 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=0 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=1 ccd7=1 elow=2000 ehigh=7200 spectrumcontrol=2 bindl=1.3388 bindh=0.9997 bnorm=2160

     proton prefix=S005 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 \
      elow=400 ehigh=1250 spectrumcontrol=2 bindl=2.5829 bindh=0.0636 bnorm=0.3533

     proton prefix=S005 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 \
      elow=3000 ehigh=7200 spectrumcontrol=2 bindl=2.5829 bindh=0.0636 bnorm=0.3533

  12. rot-im-det-sky uses information in a previously created count image in sky coordinates to rotate the detector coordinate soft proton background images into sky coordinates.

     rot-im-det-sky prefix=1S003 mask=0 elow=400 ehigh=1250 mode=2
     rot-im-det-sky prefix=1S003 mask=0 elow=2000 ehigh=7200 mode=2
     rot-im-det-sky prefix=2S004 mask=0 elow=400 ehigh=1250 mode=2
     rot-im-det-sky prefix=2S004 mask=0 elow=2000 ehigh=7200 mode=2
     rot-im-det-sky prefix=S005 mask=0 elow=400 ehigh=1250 mode=2
     rot-im-det-sky prefix=S005 mask=0 elow=2000 ehigh=7200 mode=2

    At this point all of the components for all three instruments are ready to create an image. Figure 7 displays the components for MOS1.

    Figure 7: MOS1 image components with the count image which also shows the excluded point source regions (upper left), exposure image (upper right), QPB image (lower left), and soft proton image lower right.

  13. comb combines the MOS1, MOS2, and pn images, as well as images from multiple exposures. Since the spectra and images were created with point sources removed comb must be run using the cheese masking.

     comb caldb=/XMM/sas/CCF/esas/ withpartcontrol=1 withsoftcontrol=1 withswcxcontrol=0 \
      elowlist=400 ehighlist=1250 mask=1 prefixlist="1S003 2S004 S005"

     comb caldb=/XMM/sas/CCF/esas/ withpartcontrol=1 withsoftcontrol=1 withswcxcontrol=0 \
      elowlist=2000 ehighlist=7200 mask=1 prefixlist="1S003 2S004 S005"

    Figure 8 shows the merged component images.

    Figure 7: Merged image components with the count image (upper left), exposure image (upper right), QPB image (lower left), and soft proton image lower right. The negative counts in the count image are an artifact of the pn OOT correction.

  14. adapt adaptively smooths the images.

     adapt smoothingcounts=50 thresholdmasking=0.02 detector=0 binning=2 elow=400 ehigh=1250 \
      withmaskcontrol=no withpartcontrol=yes withsoftcontrol=yes withswcxcontrol=0

     adapt smoothingcounts=50 thresholdmasking=0.02 detector=0 binning=2 elow=2000 ehigh=7200 \
      withmaskcontrol=no withpartcontrol=yes withsoftcontrol=yes withswcxcontrol=0

  15. Rename and display the smoothed images

     mv adapt-400-1250.fits adapt-400-1250-full.fits
     mv adapt-2000-7200.fits adapt-2000-7200-full.fits
     ds9 adapt-400-1250-full.fits adapt-2000-7200-full.fits &

    Figure 9 shows the final adaptively smoothed, background subtracted, and exposure corrected images.

    Figure 9: Abell 1795 adaptively smoothed, background subtracted, and exposure corrected images in the 0.4-1.25 keV and 2.0-7.2 keV bands.

  16. Now, redo the processing to limit the spectrum to the outer annulus. This excludes the bright cluster emission at the center of the field of view and will produce a better fit for the SP contamination. In this case this will reduce the fitted amount of SP contamination. Create the regm1-ann.txt, regm2-ann.txt, and regpn-ann.txt selection expressions. Note that the regions should cover the same part of the sky. Since the pn optical axis is offset from the center of the detector so on-axis sources will not fall in the chip gap, the annulus is smaller than the active areas.

    regm1-ann.txt: &&((DETX,DETY) IN circle(134,-219,14200))&&!((DETX,DETY) IN circle(134,-219,10600))
    regm2-ann.txt: &&((DETX,DETY) IN circle(6,-93,14200))&&!((DETX,DETY) IN circle(6,-93,10600))
    regpn-ann.txt: &&((DETX,DETY) IN circle(59,-10,14200))&&!((DETX,DETY) IN circle(59,-10,10600))

    Run mos-spectra, pn-spectra, mos_back, and, pn_back to do the spectral extraction and prepare for the background modeling. Use band limits of 0 0 since we aren't interested in recreating the image components.

     mos-spectra prefix=1S003 caldb=/XMM/sas/CCF/esas/ region=regm1-ann.txt mask=1 \
       elow=0 ehigh=0 ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos-spectra prefix=2S004 caldb=/XMM/sas/CCF/esas/ region=regm2-ann.txt mask=1 \
       elow=0 ehigh=0 ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     pn-spectra prefix=S005 caldb=/XMM/sas/CCF/esas/ region=regpn-ann.txt \
       mask=1 elow=0 ehigh=0 pattern=4 quad1=1 quad2=1 quad3=1 quad4=1

     mos_back prefix=1S003 caldb=/XMM/sas/CCF/esas/ diag=0 elow=0 ehigh=0 \
       ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     mos_back prefix=2S004 caldb=/XMM/sas/CCF/esas/ diag=0 elow=0 ehigh=0 \
       ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1

     pn_back prefix=S005 caldb=/XMM/sas/CCF/esas/ diag=0 elow=0 ehigh=0 \
      quad1=1 quad2=1 quad3=1 quad4=1

  17. For convenience, rename a few files so that they are not overwritten.

     mv mos1S003-obj.pi mos1S003-obj-ann.pi
     mv mos1S003.rmf mos1S003-ann.rmf
     mv mos1S003.arf mos1S003-ann.arf
     mv mos1S003-back.pi mos1S003-back-ann.pi
     mv mos1S003-obj-im-sp-det.fits mos1S003-sp-ann.fits
     mv mos2S004-obj.pi mos2S004-obj-ann.pi
     mv mos2S004.rmf mos2S004-ann.rmf
     mv mos2S004.arf mos2S004-ann.arf
     mv mos2S004-back.pi mos2S004-back-ann.pi
     mv mos2S004-obj-im-sp-det.fits mos2S004-sp-ann.fits
     mv pnS005-obj-os.pi pnS005-obj-os-ann.pi
     mv pnS005-obj.pi pnS005-obj-ann.pi
     mv pnS005-obj-oot.pi pnS005-obj-oot-ann.pi
     mv pnS005.rmf pnS005-ann.rmf
     mv pnS005.arf pnS005-ann.arf
     mv pnS005-back.pi pnS005-back-ann.pi
     mv pnS005-obj-im-sp-det.fits pnS005-sp-ann.fits

  18. Group the spectral data in preparation for spectral fitting.

     specgroup spectrumset=mos1S003-obj-ann.pi mincounts=100 rmfset=mos1S003-ann.rmf \
      arfset=mos1S003-ann.arf backgndset=mos1S003-back-ann.pi groupedset=mos1S003-obj-ann-grp.pi

     specgroup spectrumset=mos2S004-obj-ann.pi mincounts=100 rmfset=mos2S004-ann.rmf \
      arfset=mos2S004-ann.arf backgndset=mos2S004-back-ann.pi groupedset=mos2S004-obj-ann-grp.pi

     specgroup spectrumset=pnS005-obj-os-ann.pi mincounts=100 rmfset=pnS005-ann.rmf \
      arfset=pnS005-ann.arf backgndset=pnS005-back-ann.pi groupedset=pnS005-obj-os-ann-grp.pi

  19. Determine the solid angle and fit the data.

     proton_scale caldb=/XMM/sas/CCF/esas/ mode=1 detector=1 maskfile=mos1S003-sp-ann.fits \
       specfile=mos1S003-obj-ann.pi

     proton_scale caldb=/XMM/sas/CCF/esas/ mode=1 detector=2 maskfile=mos2S004-sp-ann.fits \
       specfile=mos2S004-obj-ann.pi

     proton_scale caldb=/XMM/sas/CCF/esas/ mode=1 detector=2 maskfile=pnS005-sp-ann.fits \
       specfile=pnS005-obj-ann.pi

    Fit the spectral data to determine the soft proton contamination parameters (Xspec XCM file). Note that the fitting process is complicated with a strong likelihood of local minima. The Al, Si, and Cu fluorescent background lines in particular should start frozen until a reasonably good fit is achieved and then thawed. After a new, and probably a significantly better fit is achieved they can be frozen again to reduce the number of free parameters and again improve the fit.

    The result of the annular fitting process is shown if Figure 10. The cluster emission is now relatively minor allowing for a much improved fit to the various background components.

    Figure 10: Best fit of the Abell 1795 data from the outer annulus. The green data and model curves are from the pn, the black and red data and model curves are from the MOS1 and MOS2, respectively, and the blue model and curve are from the RASS. The straight line model curves for the MOS and pn are the soft proton contribution.

  20. Scale the fitted SP results for the limited region to the whole FOV. sp_partial scales the normalization from one extracted region to that of another, in this case the full FOV.

     sp_partial caldb=/XMM/sas/CCF/esas/ detector=1 fullimage=mos1S003-sp-full.fits \
      fullspec=mos1S003-obj-full.pi regionimage=mos1S003-sp-ann.fits \
      regionspec=mos1S003-obj-ann.pi rnorm=3.33912E-02

     sp_partial caldb=/XMM/sas/CCF/esas/ detector=2 fullimage=mos2S004-sp-full.fits \
      fullspec=mos2S004-obj-full.pi regionimage=mos2S004-sp-ann.fits \
      regionspec=mos2S004-obj-ann.pi rnorm=3.20506E-02

     sp_partial caldb=/XMM/sas/CCF/esas/ detector=3 fullimage=pnS005-sp-full.fits \
      fullspec=pnS005-obj-os-full.pi regionimage=pnS005-sp-ann.fits \
      regionspec=pnS005-obj-os-ann.pi rnorm=4.80088E-02

  21. proton uses the fitted soft proton parameters to create images of the soft proton contamination in detector coordinates. Use the fitted power law index from the annular fit.

     proton prefix=1S003 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=0 ccd7=1 elow=400 ehigh=1250 spectrumcontrol=2 bindl=1.1634 bindh=0.5636 bnorm=0.1102

     proton prefix=1S003 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=0 ccd7=1 elow=2000 ehigh=7200 spectrumcontrol=2 bindl=1.1634 bindh=0.5636 bnorm=0.1102

     proton prefix=2S004 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=0 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=1 ccd7=1 elow=400 ehigh=1250 spectrumcontrol=2 bindl=1.1634 bindh=0.5636 bnorm=0.1058

     proton prefix=2S004 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=0 ccd3=1 ccd4=1 ccd5=1 \
      ccd6=1 ccd7=1 elow=2000 ehigh=7200 spectrumcontrol=2 bindl=1.1634 bindh=0.5636 bnorm=0.1058

     proton prefix=S005 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 \
      elow=400 ehigh=1250 spectrumcontrol=2 bindl=1.8566 bindh=0.1000 bnorm=0.1826

     proton prefix=S005 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 \
      elow=3000 ehigh=7200 spectrumcontrol=2 bindl=1.8566 bindh=0.1000 bnorm=0.1826

  22. Use rot-im-det-sky again to rotate the detector coordinate soft proton background images into sky coordinates.

     rot-im-det-sky prefix=1S003 mask=0 elow=400 ehigh=1250 mode=2
     rot-im-det-sky prefix=1S003 mask=0 elow=2000 ehigh=7200 mode=2
     rot-im-det-sky prefix=2S004 mask=0 elow=400 ehigh=1250 mode=2
     rot-im-det-sky prefix=2S004 mask=0 elow=2000 ehigh=7200 mode=2
     rot-im-det-sky prefix=S005 mask=0 elow=400 ehigh=1250 mode=2
     rot-im-det-sky prefix=S005 mask=0 elow=2000 ehigh=7200 mode=2

  23. comb combines the MOS1, MOS2, and pn images, as well as images from multiple exposures. Since the spectra and images were created with point sources removed comb must be run using the cheese masking.

     comb caldb=/XMM/sas/CCF/esas/ withpartcontrol=1 withsoftcontrol=1 withswcxcontrol=0 \
      elowlist=400 ehighlist=1250 mask=1 prefixlist="1S003 2S004 S005"

     comb caldb=/XMM/sas/CCF/esas/ withpartcontrol=1 withsoftcontrol=1 withswcxcontrol=0 \
      elowlist=2000 ehighlist=7200 mask=1 prefixlist="1S003 2S004 S005"

  24. Adaptively smooth the images.

     adapt smoothingcounts=50 thresholdmasking=0.02 detector=0 binning=2 elow=400 ehigh=1250 \
      withmaskcontrol=no withpartcontrol=yes withsoftcontrol=yes withswcxcontrol=0

     adapt smoothingcounts=50 thresholdmasking=0.02 detector=0 binning=2 elow=2000 ehigh=7200 \
      withmaskcontrol=no withpartcontrol=yes withsoftcontrol=yes withswcxcontrol=0

  25. Rename and display the smoothed images.

     mv adapt-400-1250.fits adapt-400-1250-ann.fits
     mv adapt-2000-7200.fits adapt-2000-7200-ann.fits
     ds9 adapt-400-1250-ann.fits adapt-2000-7200-ann.fits

    Figure 11 shows the final adaptively smoothed, background subtracted, and exposure corrected images, this time with the better parametrization of the background components allowed by using the outer annulus. The effect is most clearly shown in the 0.4-1.25 keV band where the background is no longer over-subtracted.

    Figure 11: Abell 1795 adaptively smoothed, background subtracted, and exposure corrected images in the 0.4-1.25 keV and 2.0-7.2 keV bands.

  26. If necessary (not in this observation) the task swcx can be used to model the contribution of SWCX to the image to be subtracted. swcx uses the fitted values for SWCX lines fluxes to model their image contributions.

     swcx prefix=1S003 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1 \
      elow=400 ehigh=1250 linelist='1 2' gnormlist='0.0 7.65634E-08' objarf=mos1S003-full.arf \
      objspec=mos1S003-obj-full.pi

     swcx prefix=2S004 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 ccd5=1 ccd6=1 ccd7=1 \
      elow=400 ehigh=1250 linelist='1 2' gnormlist='0.0 7.65634E-08' objarf=mos2S004-full.arf \
      objspec=mos2S004-obj-full.pi

     swcx prefix=S005 caldb=/XMM/sas/CCF/esas/ ccd1=1 ccd2=1 ccd3=1 ccd4=1 elow=400 ehigh=1250 \
      linelist='1 2' gnormlist='0.0 7.65634E-08' objarf=pnS005-full.arf objspec=pnS005-obj-full.pi

  27. SWCX images are also created in detector coordinates and so must be rotated into sky coordinates.

     rot-im-det-sky prefix=1S003 mask=0 elow=400 ehigh=1250 mode=3
     rot-im-det-sky prefix=2S004 mask=0 elow=400 ehigh=1250 mode=3
     rot-im-det-sky prefix=S005 mask=0 elow=400 ehigh=1250 mode=3

  28. comb combines the MOS1, MOS2, and pn images, as well as images from multiple exposures. Since the spectra and images were created with point sources removed comb must be run using the cheese masking.

     comb caldb=/XMM/sas/CCF/esas/ withpartcontrol=1 withsoftcontrol=1 withswcxcontrol=1 \
      elowlist=400 ehighlist=1250 mask=1 prefixlist="1S003 2S004 S005"

     comb caldb=/XMM/sas/CCF/esas/ withpartcontrol=1 withsoftcontrol=1 withswcxcontrol=1 \
      elowlist=2000 ehighlist=7200 mask=1 prefixlist="1S003 2S004 S005"

  29. Adaptively smooth the images.

     adapt smoothingcounts=50 thresholdmasking=0.02 detector=0 binning=2 elow=400 ehigh=1250 \
      withmaskcontrol=no withpartcontrol=yes withsoftcontrol=yes withswcxcontrol=0

     adapt smoothingcounts=50 thresholdmasking=0.02 detector=0 binning=2 elow=2000 ehigh=7200 \
      withmaskcontrol=no withpartcontrol=yes withsoftcontrol=yes withswcxcontrol=0

  30. Rename and display the smoothed images.

     mv adapt-400-1250.fits adapt-400-1250-ann-swcx.fits
     mv adapt-2000-7200.fits adapt-2000-7200-ann-swcx.fits
     ds9 adapt-400-1250-ann-swcx.fits adapt-2000-7200-ann-swcx.fits



Caveats

For information about known issues, refer to the ESAS Warnings and Watchouts pages.



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This page was last updated on 10 November, 2014.