XMM-Newton Science Analysis System


omgrism (omgrism-1.31) [22.0.0-9173c7d25-20250127]

Algorithm

   subroutine omgrism

     read parameters

     get handle on source rates file
     
     check if this file contains data 

     get handle on the input image file     

     check if the image file corersponds to the Grism-1 or Grism-2 filters

     set the grism-state for the CAL routines
 	
     get CAL plate scale 

     get the number of sources detected by omdetect

     allocate indicators for source shapes and source relations

     loop source=0, nSources

       determine the source shape and classify each source 
       according to the filter-dependents specific criteria

     end loop

     loop source=0, nSources
  
       if source is extended (first-order)

	 loop iSource=0, nSources

	    check if the extended source  corresponds to a 
            point-like source (zero-order) by the criteria
            corresponding to the given Grism filter
            and mark the zero- and first-order sources as 
            related to each other

         end loop

       end if	

     end loop

     loop source=0, nSource

	if source is marked as having a corresponding zero-order 
        within the image then extract the spectrum and add 
        the corresponding data table to the output FITS-file

     end loop

     write spectra keywords to header

     write output spectrum file

     release handles

   end subroutine omgrism