For all sources from the isgri_srcl_res.fits file, ii_lc_extract
extracts the ISGRI lightcurves.
The results are written to the ISGR-SRC.-LCR and ISGR-SRC.-LCR-IDX Data Structures.
ISGR-SRC.-LCR has the same structure as PICS-EVTS-LCR,
see Table 57
Table 58:
Content of the ISGR-SRC.-LCR-IDX Data Structure.