NAME

xrtexpomap -- Generate exposure maps for XRT Photon Counting and Windowed Timing modes event files.

USAGE

xrtexpomap infile outfile [parameter=value ... ]

DESCRIPTION

'xrtexpomap' generates an exposure map that accounts for CCD bad pixels and columns, attitude variations and telescope vignetting for Photon Counting and Windowed Timing event files.
'xrtexpomap' creates at first time dependent instrument maps in raw coordinates where bad pixels and columns within the XRT field of view and the CCD readout window are marked. The time dependent instrument maps are transformed in sky through the task 'swiftxform' using the attitude information. Last the different instrument maps in sky coordinates are summed. The final exposure map in sky coordinates contains in each pixel the net exposure time.
The integration of each instrument map depends on the number of CCD frames included. This can be set with the parameters 'pcnframe' and 'wtnframe'. If 'pcnframe' and/or 'wtnframe' parameter is set to '0' time dependent instrument maps are generated for the specific datamode when the attitude flag changes from 'settled' to 'slew' or if two subsequent frames are separated by more than 100 seconds. By setting the parameter 'checkattitude'="yes" when 'pcnframe'=0 and/or 'wtnframe'=0, time dependent instrument maps are generated if, within a given set of consecutive frames, the spacecraft attitude variations are larger than 2.4 arcsec (corresponding to approximately 1 detector pixel).
The instrument maps are stored as FITS IMAGE extensions in a file. If the parameter 'vigflag' is set to 'yes','xrtexpomap' applies the vignetting correction to the raw instrument map using the vignetting CALDB file or in a file provided by the user (parameter 'vigfile').

For WT data taken during spacecraft settling, the attitude file corrected for jumps from the archive (sw*pat.fits) must be used.

PARAMETERS

infile [file name]
Name of the input cleaned event FITS file.

attfile [file name]
Name of the input Attitude FITS file.

hdfile [file name]
Name of the input Housekeeping Header Packets FITS file.

(stemout = DEFAULT)
Stem for the output files. If stemout=DEFAULT, the standard naming convention will be used.

(fovfile = CALDB)[file name]
Name of the file containing the Field of View geometry description. If set to CALDB (default value) use the file in the Calibration Database.

(vigfile = CALDB) [file name]
Name of the input vignetting FITS file. If set to 'CALDB' (default value) use the file in the Calibration Database.

(vigflag = no) [boolean]
If set to 'yes', apply the vignetting correction.

(energy = 1.5) [real]
Energy value for vignetting calculation.

(pcnframe = 0) [integer]
Number of frames considered together in the instrument map calculation for PC (POINTING mode only). If set to 0, produce an instrument map for a set of consecutive frames separated by less than 100 seconds.

(wtnframe = 0) [integer]
Number of frames considered together in the instrument map calculation for WT (POINTING mode only). If set to 0, produce an instrument map for a set of consecutive frames separated by less than 100 seconds.

(checkattitude = yes) [boolean]
If 'checkattitude'=yes and 'pcnframe'=0 and/or 'wtnframe'=0, checks pointing stability in the instrument map calculation.

outdir [directory name]
Directory for the output files.

(teldef = CALDB) [file name]
Name of the teldef calibration file. If set to CALDB, use the file in the Calibration Database.

(cleanup = yes) [boolean]
If set to 'yes', delete temporary files.

(history=yes) [boolean]
If set to yes, write parameter values and other information in HISTORY blocks.

(clobber=no) [boolean]
If 'clobber'=yes and outfile=filename, the file with the same name will be overwritten, if it exists.

(chatter = 2) [integer]
Chatter Level (min=0, max=5).

EXAMPLES

  1. Produce an exposure map in the current directory for the Photon Counting mode event file sw00158855000xpcw2po_cl.evt. The vignetting correction is applied, the name of the output exposure map, sw00158855000xpc_ex.img, is assigned according to the standard naming convention and a set of intermediate files is also saved in the current directory. 

     > xrtexpomap infile=sw00158855000xpcw4po_cl.evt attfile=sw00158855000sat.fits 
              hdfile=sw00158855000xhdtc.hk pcnframe=4 vigflag=yes outdir=./ cleanup=no

BUGS

SEE ALSO

LAST MODIFIED

June 2014