subroutine backcorr Arfgen computes the effective area curves for both the source (arf_in_src.arf) and background (arf_in_bkg.arf) regions. The extraction region is read directly in the input spectra through the data sub space. Calls the subroutine make_backcorr which : Reads in the two temporary arf files: arf_in_src.arf & arf_in_bkg.arf Reads in the input background spectrum (==> bkg_input_spectrum) Makes the appropriate correction : bkg_corrected_spectrum=(arf_src/arf_bkg)*bkg_input_spectrum Writes out bkg_corrected_spectrum into a FITS file with the same header of the input file + an updated history End of make_backcorr Delete temporary arf files if not requested to be kept end subroutine backcorr