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 19.
It is also possible to combine the spectra of the Science Windows which belong to different observation groups. This is explained in section 7.4.2.