Lightcurve extraction from the IMA step

IMA step of jemx_science_analysis script outputs the fluxes of all detected sources in jmxi_srcl_res.fits files. A Scw-by-Scw lightcurve of all these sources could be obtained with the help of src_collect script.

As an example, let us produce the Scw-by-Scw lightcurve of GX 354-0 in two energy bands, 3-10 keV and 10-35 keV. For this we will need first to extract fluxes from the images in these energy band in each ScW:

cd $REP_BASE_PROD 
og_create idxSwg=mos.lst ogid=ima_lc baseDir="./" instrument=JMX2 
cd obs/ima_lc
jemx_science_analysis startLevel="COR" endLevel="IMA" jemxNum=2\
   nChanBins=2 chanLow="46 129" chanHigh="128 223"

For each source, IMA step output contains fluxes in 3 ``standard'' IMA energy bands, plus the fluxes in the energy bins specified by nChanBins, chanMin and chanMax parameters.

To extract the ScW-by-ScW lightcurve from the images one has to run the script

src_collect group=og_jmx2.fits+1 results=GX354_scw_lc.fits\
   instName=JMX2 select="NAME == 'GX 354-0' "

As a result, the file GX354_scw_lc.fits will contain the source lightcurves in the 3 standard and the user-defined energy bands. To display the lightcurve e.g. in the 1st user defined energy band (3-10 keV) in our example you can use the fv program to plot the FLUX[4], FLUXERR[4] vs. TSTART. The [4] in the square brackets signifies that one wants to plot the 4-th energy band (remember that the first three bins always contains the fluxes in the detection images, so the first user bin is the 4th one). One can extract the light curve in a single energy bin usuing the following command:

fcopy "GX354_scw_lc.fits [col TIME=(TSTART+TSTOP)/2; RATE = FLUX[4];\
   ERROR = FLUX_ERR[4]]" light_curve.fits.

This file can be visualized with lcurve as explained above.

Note, that the source GX 354-0 is a bright X-ray binary which is detected in each ScW, so that information about the source flux in each ScW is always available in the jmx2_srcl_res.fits files. For a weaker source, like 1E 1740.7-2942, which is not always detected in single ScWs, one has to "force" jemx_science_analysis to output information about the flux (or an upper limit on the flux) of the source into jmx2_srcl_res.fits files in each ScW by running the analysis with the user-defined input source catalog, as it is explained in section 7.5.