Combining spectra and lightcurves from different observation groups

In sections 6.7.5 and 6.8.3 you have seen how to merge lightcurves and spectra from different Science Windows belonging to the same group. In that case the file og_jmx2.fits points to all the Science Windows and it is possible to launch the collecting/merging tools lc_pick and spe_pick directly on the group (group=og_jmx2.fits+1).

If you have Science Windows belonging to different groups, you need an intermediate step. Basically you need to create a file (an index) that points to all the Science Windows you want to co-add, similarly to the case seen in the previous section. Then this file will be given as input via the "group" parameter at the place of og_jmx2.fits.

To create the index make a list of the Science Window groups you want to combine and save it as, e.g., dols.txt under $REP_BASE_PROD/obs/. To ensure a proper work of the software give the full path, i.e. your file should look like

/WORKING-DIR/obs/GROUP1/scw/011901060010.001/swg_jmx2.fits
/WORKING-DIR/obs/GROUP1/scw/011901070010.001/swg_jmx2.fits
/WORKING-DIR/obs/GROUP2/scw/012000360010.001/swg_jmx2.fits
/WORKING-DIR/obs/GROUP2/scw/012000370010.001/swg_jmx2.fits

The first 2 files belong to a run with the og_create parameter "ogid" equal to "GROUP1" while the latter two to a run with "ogid" equal to "GROUP2". /WORKING-DIR/ has to be the extensive name of $REP_BASE_PROD. WARNING: make sure that the lightcurve and spectra files exist for each Science Window you want to co-add (jmx2_src_lc.fits and jmx2_srcl_spe.fits files).

Then give the command that actually builds the fits file from the ASCII file:

cd $REP_BASE_PROD/obs/
txt2idx element="dols.txt" index="index_comb_2.fits"

Then run lc_pick and spe_pick putting the parameter "group" equal to "index_comb_2.fits":

cd $REP_BASE_PROD/obs/
lc_pick source="J180108.2-250445" attach=n \
   group=index_comb_2.fits+1 lc=GX5-1.lc.fits emin="3.04"  \
   emax=10.08 instrument="JMX2"

GX5-1.lc.fits contains the merged lightcurve of GX5-1 (source_ID=J180108.2-250445, as can be seen e.g. in the ISDC reference catalog) in the 3.04-10.08keV band (energy range that of course has to exist in the jmx2_src_lc.fits original files!). Using lc_pick without specifying the energy range, will produce an output file with multiple extensions, one per available energy range.

cd $REP_BASE_PROD/obs
spe_pick group="index_comb_2.fits"\
   source="GX 5-1" rootname="GX5-1"  instrument="JMX2"

GX5-1_sum_pha.fits (the combined spectrum of GX 5-1) and GX5-1_single_pha2.fits (a file with the four spectra of the initial four Science Windows collected together) are created. spe_pick also creates an ARF, appropriate for your particular dataset. This ARF is written to GX5-1_sum_arf.fits and GX5-1_single_arf2.fits files. The names of the response and ancrfile are inserted in the keyword of the final files, so that they are automatically recognised by XSPEC.