XMM-Newton Science Analysis System


especplot (especplot-2.10.1) [22.0.0-9173c7d25-20250127]

Algorithm

   Subroutine especplot


     Recover parameters (Filenames, Binning mode, Device type)
        
     Read source (Src) and background (Bkg) spectrum FITS files : 
          Get dataset and table.
          Check if important keywords exist and are correct.
          Call an error if not.
          Recover counts and channel columns.
        
     Get energy boundaries (Emin, Emax) using 1PI=1eV
        
     Open plot :
         Create view surface in specified device format.
         Write labels on it.

     Allocate six vectors with Emin&Emax size :
          Emed = (Emin + Emax)/2
          Edelta = (Emin - Emax)/2
          Net_Counts = Src_Counts - 
                Bkg_Counts*Src_Exposure_Time/Bkg_Exposure_Time
          Net_Counts_Err = sqrt(Src_Counts + Bkg_Counts*
                ((Src_Exposure_Time/Bkg_Exposure_Time)**2))
          Bkg_Counts which yet exists
          Bkg_Counts_Err = sqrt(Bkg_Counts)

     For Net_Counts and Bkg_Counts do :

          Rebin Emed, Edelta, Counts, Counts_Err following the specified
          binning scheme (auto, size).

          Normalize Counts and Counts_Err.

          In the new vectors, eliminate each value where :
                (Emed-Edelta<=0) or (Counts-Counts_Err<=0)      

          Plot Y=log(Counts) as a function of X=log(Emed)

          Draw errors on plotted points :
                  log(Counts_Err) for Y-axis
                  log(Edelta) for X-axis
     End for

     Return plot on device selected.

     Release memory.

     Close plot.

   End subroutine  especplot