xtecol HEADAS help file

NAME

xtecol -- creates a collimator corrected light curve for an XTE PCA input light curve.

USAGE

        xtecol lcfile outfile xtefilt pcu collcube

DESCRIPTION

This task computes the collimator correction for an XTE (PCA or HEXTE) light curve. It computes the correction from the source position and the instrument pointing. If the jitter in the pointing is less than the nominal jitter, then an average pointing is used for the entire light curve. The collimator correction value corresponding to this average pointing is stored as a keyword value in the extension header of the output file. If the jitter is greater than the nominal jitter, then the current pointing is used for each time in the light curve. In the latter case, if the sampling (i.e. bin size) in the light curve is less than the sampling rate in the pointing, then the pointing is obtained via interpolation. On the other hand, if the sampling in the light curve is larger than that of the pointing, then an average pointing over the duration of the bin is used. The user may override the nominal jitter criterion via the hidden jitter parameter.

If the source lies outside of the field of view, a warning message is given and the returned intensity is set to INDEF for that time stamp. The input file is copied to the output file. Intensities for times lying outside the desired start and stop times are given a value of INDEF. When quaternions are not available for a desired time, the rate is also given a value of INDEF.

PARAMETERS

lcfile [file name]: The name of the input light curve file. Currently, only scalar ("type I") files are handled intentionally. Vectored light curve files ("type II") may be handled correctly by accident.
outfile [file name]: The name of the output light curve file.
xtefilt [file name]: The file containing the satellite pointing for the input pha file. This may be either the XTE FILTER file, or the quaternion file (FH0e...). The user may also input an ascii file @filename containing the path to the file.
collcube [file name]: The name of the collimator cube file for the appropriate pcu. A value of CALDB (or "caldb") will retrieve the appropriate cube from the calibration database.
detnam [string]: The detector of interest, corresponding to a DETNAM keyword in the collimator FITS file (collcube).
(ra = 'INDEF') [real*4]: An alternate right ascension for the object.
(dec = 'INDEF') [real*4]: An alternate declination for the object.
(jitter= 20.0) [real*4]: The acceptable amount of jitter in the spacecraft pointing, in arc seconds.
(start = -1.) [real*4]: An alternate start time for the observation.
(stop = -1.) [real*4]: An alternate stop time for the observation.
(chatter = 9) [integer]: The standard chatter parameter.
(clobber = no) [string]: Delete output file if it exists ? (Override with !filename)
(arfversn = 1.1.0) [string]: Version number for the type of .arf file to output

EXAMPLES

1. Construct the collimated corrected light curve for the file std2one.lc, using the quaternion files FH0e_2e89a5c-2e90abf. The input file represents the intensity from all the detectors (pcu=all). The collimator cube file will be fetched from caldb, and the output light curve will be written to std2one_col.lc.

       xtecol std2one.lc std2one_col.lc FH0e_2e89a5c-2e90abf ALL CALDB

2. Construct the collimated corrected light curve for the file hexte_a.lc, using the quaternion file FH0e_2e89a5c-2e90abf. The input file represents the intensity from all the detectors (detnam=PWA). The collimator cube file will be fetched from caldb, and the output light curve will be written to hexte_a_col.lc.

       xtecol hexte_a.lc hexte_a_col.lc FH0e_2e89a5c-2e90abf PWA CALDB

NOTES:

BUGS

Please report problems to xtehelp@athena.gsfc.nasa.gov.