Problems based on the analysis of
the Crab
ISGRI
list of data for this task
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.
PICsIT
List
of data for this task
Create mosaic images in default set of energy bands.
Determine the position of the Crab and compare with the catalog one.
Compare the accuracy of localization for different energy bands.
Buid a Crab spectrum from the images.
Create the lightcurve of the PICsIT detector.
JEM-X
Create the JEM_X image of Crab with and without vignetting correction.
Compare the quality of the obtained images. Determine the position of
Crab and compare it with the catalog position.
Create the JEM_X mosaic image .
Determine the spectrum of Crab for each science window and sum
the spectra from individual science windows into a single summary
spectrum. Determine the flux
in 3-5 keV energy band in cts/sec with the help of xspec
command
ignore **-3.
5.-**
show rate
as well as in erg/(cm^2 s) with the help of xspec
command
flux 3. 5.
Produce 10-second resolution X-ray lightcurve of Crab in each science
window and then combine the obtained lightcurves in a single summary
lightcurve. Compare the Crab flux
found from the spectral analysis
with the flux which you find from
the lightcurve.
With the help of
xspec combine the spectra from JEM-X and ISGRI to obtain
the spectrum of Crab in the energy 3-200 keV energy range (load the two
spectra simultaneously with the help of data 1:1 and data 2:2
commands). Study the problem of cross-calibration of the
two
instruments.
3. Timing Analysis.
Lightcurve production
Create 20-40 keV Crab lightcurve in Window mode. Use a timing
scale of about one hour (i.e. 0.05)!
Note: remember that this way
it is impossible to generate light curves with a resolution of less
than one scw!
Timing analysis with the Revision 2 data
To use revision 2 data you will have to set the environment once again.
Create data_rep_rev2 directory and repeat the procedure
described
at the top of this
page substituting rev_2 instead of rev_1.
For the examples on the use of revision 2 data see
http://isdc.unige.ch/~ebisawa/Crab-Timing/crab.html