XMM-Newton Science Analysis System


espfilt (espfilt-5.0.2) [xmmsas_20230412_1735-21.0.0]

Algorithm

Below is the algorithm for the CORNER METHOD
   subroutine espfilt
      Read parameters.	
       Create these with evselect
        FOV image
        FOV lightcurve
        Corner event list
        Corner image
        Corner lightcurve
        if (method .eq. ratio)
         Create FOV annulus event list
         Create FOV annulus image
         Create FOV annulus lightcurve
        endif
       Call method
        if (method .eq. histogram) then 
	 call histogram_method
	 subroutine histogram_method:
          Construct intermediary file names (QDP, GTI)
	  call clean_lc (based on clean_rel.pro)
	  subroutine clean_lc:
	   extract columns TIME, RATE from FOV LC
	   extract columns TIME, RATE from corners LC
	   bin TIME, RATE columns from object LC
	   bin TIME, RATE columns from corners LC
	   smooth RATE column from object LC
	   smooth RATE column from corners LC
           create histogram sortindex array
           fill sortindex as simple histogram of counts
           find peak of the distibution
           run downhill simplex multi-D minimization of 
           gaussian fit function
           verify goodness of fit
           call write_qdp_gti to create output quicklooks
	  end clean_lc	   
	  call gauss_fit 
         end histogram_method 
	elseif (method .eq. ratio) then 
	 call ratio_method
 	 subroutine ratio_method:
          extract corner spectrum
          backscale corner spectrum
          extract FOV annulus spectrum 
          backscale FOV annulus spectrum 
          read exposure, backscal, counts from Corner data.
          read exposure, backscal, counts from FOV Ann data.
	  create ratio of FOV annulus to corner:
	   ratio =  fovann_counts / corner_counts * \
           (corner_time * corner_area) / \
           (fovann_time * fovann_area) 
           call clean_lc as above
	  create ratio of FOV annulus to corner LC
	  create GTI for time intervals when FOV\/corner 
          ratio acceptable
          call write_qdp_gti to create output quicklooks
	 end ratio_method
	end call_method
        Create these with evselect:
         FOV filtered (flare-free) event list
         FOV filtered (flare-free) image
         Corner filtered (flare-free) event list
         Corner filtered (flare-free) image
        Add EHIGH, ELOW attributes to products
        Add fit parameters attributes to products:
         NORM, WIDTH, CENTER
         H_IMME, H_TOTL, L_IMME, L_TOTL
       end espfilt
	subroutine write_qdp_fit
	 open QDP output file
	 write header, title information
	 write out count rate histogram
	  overlay selection and fit limits
	 write out FOV lightcurve
	  overlay GTIs
	 write out Corner lightcurve
	  overlay GTIs
	 open ASCII gti.txt file
	  write out GTIs to ASCII
	 task gtibuild create GTI fits file
        end subroutine write_qdp_fit