hriexpmap -- creates an exposure map for a given ROSAT HRI observational dataset
hriexpmap ltffil attfil gtifil dmapfil outfil rolof
This task creates an exposure map for a ROSAT HRI pointed
observation.(The task is essentially an FTOOLized version of Steve Snowden's CAST_EXP_HRI code). A detector map created from the accumulated bright Earth data is required. The output is a 512x512 FITS image of the whole HRI field of view (with pixels 5.0 arcsec per side; representing a blocking factor of 10 over the 0.5 arcsec sky pixelsize) of the effective exposure time (in seconds) at that position. The effects of vignetting (for X-rays at 0.53 keV) and spatial variations in the efficiency of the detector are included (via the detector map), along with detector deadtime effects (from the deadtime correction file provided with the observation data set).
In brief, the attitude and GTI files are used to construct a matrix of
the time the instrument spent at each pointing position (X,Y relative to the nominal pointing position defined by the optical axis) and roll angle. (The digitizations in X and Y are in steps of 5 arcsec, the digitization in ROLL angle is in steps of 0.004 radians.) The livetime correction file is then used to scale observation time at each of these positions. Finally the output exposure map is constructed by moving the detector map to each off-axis position, rotated to each roll angle, and adding the detector map with the appropriate weighting factor to the exposure map under construction.
The current version of this task will only operate on i/p datasets in US Rev0 format or RDF format (ie cannot read German/UK Rev0 datasets). Furthermore all i/p datasets must be in the same format.
NOTE : This program takes a long time to cast the exposure, it is usefull to have the chatter value >= 9 (see parameters section), as reassuring % completion values are printed.
This example uses the RDF dataset rh900385n00 and assumes that the HEASARC CALDB is being accessed remotely; see http://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/caldb_remote_access.html for more information on how to access the HEASARC CALDB remotely
% printenv CALDB % ftp://heasarc.gsfc.nasa.gov/caldb % hriexpmap Please enter EVRATE/LIVETIME filename:[] rh900385n00_anc.fits Please enter Attitude filename:[%] % Please enter GTI filename:[none] rh900385n00_bas.fits Please enter Detector map file:[caldb] ... using gtcalf 1.1.1 ... using caldb_info 1.2.1 ...... environ-var/logical CALDB defined ......... CALDB path = ftp://heasarc.gsfc.nasa.gov/caldb ...... environ-var/logical CALDBCONFIG defined ......... CALDBCONFIG file = /software/caldb/caldb.config ...... environ-var/logical CALDBALIAS defined ......... CALDBALIAS file = /software/caldb/alias_config.fits ...... CALDB is configured for the HRI instrument onboard ROSAT ......... Cal Index File: ftp://heasarc.gsfc.nasa.gov/caldb/data/rosat/hri/caldb.indx ......... Data directory: ftp://heasarc.gsfc.nasa.gov/caldb/data/rosat/hri ... using cifsl2 5.0.4 ...... Downloading be.fits Please enter output filename[] rh900385n00_mex.fits Please enter ROLL offset (for RDF enter 0) in radians:[0] ** hriexpmap 1.1.4 ...... ... LIST LENGTH = 1746 ...... ... GOOD STEPS = 11525 ...... ... BAD STEPS = 271 ...... ... TOTALTIME = 11525.00 ...... ... TOTALEXP = 11396.88 100% completed ** hriexpmap 1.1.4 completed successfully
None known
the output MEX file has a plate scale of 5"/pixel.
Snowden et al. (1992, ApJ, 393 819)
Plucinsky et al. (1993, ApJ, 418, 519)
Rehana Yusaf
HEASARC
NASA/GFSC
http://heasarc.gsfc.nasa.gov/cgi-bin/ftoolshelp
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