Problems based on the analysis of
the Crab
ISGRI
1.Get your data
Using the INTEGRAL Archive Browse find the Science WIndows (ScW) of
revolution 102 in which Crab pulsar wind nebulae is observed almost
on-axis (off-axis angle is less than 10 arcmin). Select several of them
for the analysis.
Using the list of data given above create an observation group named crab_isgri
1. Image Reconstruction:
Run ibis_science_analysis
from COR till IMA
step in 3 energy bands (20-40 keV, 40-60 keV, 60 -100 keV).
( IBIS_II_E_band_min="20
40 60"
IBIS_II_E_band_max="40 60 100"
IBIS_II_ChanNum=3 ).
Determine the position of the Crab and compare with the catalog one.
Compare the accuracy of localization for different energy bands.
Create and compare mosaic images with and without background
subtraction.
With the help of cat2ds9 create
a region file of detected and
catalog sources and
create a nice image with ds9.
Compare the Crab flux in single science windows with the flux
determined from the mosaic analysis.
2. Spectral Analysis.
Copy the IMA level group crab_isgri to crab_isgri2
to try different methods of spectral extraction.
Leave crab_isgri unmodidied as a reserve copy of the analysis
run till IMA level.
With the help of FTOOLS utility rbnrmf
rebin response
matrix for spectral analysis.
(To know more about this program type fhelp rbnrmf).
Example of binning scheme
is given in the IBIS cookbook.
Find the Crab spectrum using the standard spectral extraction method
and method based on the
mosaic image.
To sum the spectra of the single science windows use spe_pick.
The command should looks like:
spe_pick group="og_ibis.fits[1]" source="Crab"\
response=../../ic/ibis/rsp/isgr_rmf_grp_0017.fits\
ancrfile=../../ic/ibis/rsp/isgr_arf_rsp_0010.fits rootname=Crab
Launch xspec and compare
the obtained results.
3. Timing Analysis.
Lightcurve production
Create 20-25 keV Crab lightcurve with 100 sec binning.
Merge lightcurves from single science windows with the help of lc_pick.
Compare the obtained countrate with the one you found at image step in
crab_mosaic.
Timing Analysis without deconvolution
Find the Crab period.
To do this create list of photons and produce Crab power spectrum.