Analysis of a Gamma-Ray Burst


Find the basic informaiton on GRB of your choice in IBAS GRB pages.

1. Convert the information about arrival time and position of GRB into form suitable for analysis.


Find the Science Window (SCW) in which the GRB appears  from GCN notice time in UTC using

converttime

and find the ScW in which GRB occured.

2. Locate the GRB on the isgry sky image.

Create the science window list and the observation group
and run  ibis_science_analysis in this observation group till IMA level.

With the help of ds9 Determine the sources found and locate them on the image. As you can see, the GRB does not appear in the source list.
To force the OSA to analyze the GRB create your own catalog my_cat.fits, e.g. by copying one arbitrary line
from ISDC reference catalog (e.g. fcopy "$ISDC_REF_CAT[NAME == 'Crab']" my_cat.fits) and
modify my_cat.fits file by changing the source name (from Crab to GRB 030501) and entering the sky position of GRB.

If very bright sources are present in the field of view, or your GRB is very weak (check the IBAS web pages), add the most important persistent sources to your catalog.

Create a region file from my_cat.fits and locate the GRB on isgry sky image with the help of ds9. 

3.  Detailed analysis: using the user GTI.

Now when you have first information about the GRB you can do more detailed analysis.

Create an new observation group with the GRB ScW.
 
Create your own good time interval (GTI) which will select only the photons which came during the GRB.  Run the sceince analysis once more in a new observation group.

gti_user my_gti.fits TSTART TEND group=og_ibis.fits

where TSTART and TEND are in UTC. Check your GTI file with fv:

fv my_gti.fits &


Run the analysis software to make the image, 0.5 s resolution lightcurve and the spectrum of the GRB


ibis_science_analysis startLevel=COR endLevel=LCR \
CAT_refCat=my_cat.fits \
ILCR_delta_t=0.5 \
SCW1_GTI_gtiUserI=my_gti.fits

Check the results for the image, spectrum and the lightcurve.