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espfilt (espfilt-4.3) [xmmsas_20211130_0941-20.0.0]


Main loop

This task assumes that SAS tasks cifbuild, odfingest and one of the event-list producing EPIC MOS or PN task (emchain, epchain) have previously been run.

An error will result if the odfingest ASCII output file or the cifbuild FITS file are not present and set using the proper SAS environment variables or command line options.

For the Histogram Method, espfilt performs the following in sequence:

  1. The task checks to see if event list is present and has the requisite keywords.
  2. Define corner selection criteria for evselect calls.
  3. Create FOV and corner images and lightcurves with evselect.
  4. Depending on the method selected, the proper subroutine for processing via that method is envoked.
  5. For the Histogram method:
    1. Clean lightcurve in subroutine CLEAN_LC.
        Clean the light curve by creating a histogram of rate values
        from the light curve, finding the most likely value, assuming
        that to be similar to the mean of the quiescent rate, then
        fitting a Gaussian (or poissonian, or user defined curve) to 
        a small window around that value in the histogram to determine
        the true mean and dispersion of the quiescent background rate. 
        Excludes time intervals with rate higher than a multiple of
        the dispersion above the mean quiescent background and excludes
        good regions shorter than some (currently hardcoded) limit.
      

For the Ratio Method:

  1. Create FOV annulus and corner annulus images and lightcurves.
  2. Determine Counts per pixel Ratio between the FOV annulus and corners.
  3. For Time Intervals within user-selected ratio threshold ranges, select data using evselect.
For both methods, each of the following is performed
  1. Create an ASCII QDP format file.
  2. Run gtibuild.
  3. Run evselect to produce filtered, flare-free events file.
  4. Run evselect to produce filtered, flare-free image.
  5. Run evselect to produce corner-only events file.
  6. Run evselect to produce corner-only image.
  7. If PN, run evselect to produce cleaned OOT event file.

XMM-Newton SOC -- 2021-11-30