Combining Spectra of different Science Windows

With the help of the spe_pick program, described in the Introduction to the INTEGRAL Data Analysis [1], it is possible to combine the spectra from the different Science Windows. To define the source for which you want to combine the spectra you should either input its Name, Source ID, or source coordinates. In our case, to combine all the spectra belonging to the given Observation Group of the Crab, you should give the following command from $REP\_BASE\_PROD/obs/crab\_spec

spe_pick group="og_jmx2.fits[1]" instrument="JMX2"\
   source="Crab" rootname="crab"

The rootname argument allows to choose the name of the resulting spectral data files. For example, the above command produces the files

crab_single_pha2.fits	with all individual spectra of the source,
crab_single_arf2.fits	with corresponding individual ARFs,
crab_sum_pha.fits	with the combined spectrum,
crab_sum_arf.fits	with the ARF for the combined spectrum.

The resulting spectrum crab_sum_pha.fits can be analysed with XSPEC exactly in the same way as in the case of the individual ScW spectra (see above). The result of such analysis is shown in the right panel of Fig .

It is also possible to combine the spectra of the Science Windows which belong to different observation groups. This is explained in section .