NAME

hxtarf -- computes and applies the HEXTE collimator response to produce a .arf file for a HEXTE spectrum (.pha).

USAGE

        hxtarf phafil inarf outarf xtefilt collcube detname

DESCRIPTION

This task computes the collimator-corrected effective area (outarf) for a given HEXTE spectrum (phafil), using the satellite pointing information (xtefilt) and the source position. In order to do this, two calibration inputs are required: the detector-axis effective area file (inarf), and the HEXTE collimator response as a function of energy in spacecraft coordinates (collcube).

PARAMETERS

phafil [file name]

The name of the input .pha file. Both Type I (single spectrum) and Type II (multiple spectra) files are handled.

inarf [file name]

The name of the input .arf file, which contains the effective area as a function of energy for the HEXTE detector's optical axis. This file should be appropriate for the input .pha file (i.e match TELESCOP, INSTRUME, and DETNAM keywords), and be valid for on-axis datasets in detector (RAW_DET) coordinates. If "CALDB" is entered, HXTARF will search the CALDB for an appropriate dataset.

outarf [file name]

The name of the output .arf file after correction for the collimator response. This has the same energy grid as the input ARF file.

xtefilt [file name]

The XTEFILTER file containing the satellite pointing for the input .pha file.

collcube [file name]

The name of the collimator cube file for the appropriate detector, which contains the collimator response as a function of spacecraft coordinates. A value of 'caldb' may be used to search the user's caldb directory for the appropriate file.

(jitter = 25) [real*4]

The acceptable amount of "jitter" about the nominal spacecraft pointing, in arcseconds. If this value was exceeded during the observation, HXTARF will output a warning message.

detnam [string]

The name of the detector of interest. If set to 'INDEF', this is read from the DETNAM keyword of the PHA file's data extension. For the HEXTE, acceptable values are PWA0 through PWA3 (cluster A), or PWB0 through PWB3 (cluster B), or PWA (cluster A) or "PWB" (cluster B).

(ra = 'INDEF') [real*4]

An alternate right ascension for the object. If left 'INDEF', this value is read from the RA_OBJ keyword in the PHA file. If an offset pointing was requested, users may specify the true RA and Dec of their source of interest via these parameters.

(dec = 'INDEF') [real*4]

An alternate declination for the object. If left 'INDEF', this value is read from the DEC_OBJ keyword in the PHA file. If an offset pointing was requested, users may specify the true RA and Dec of their source of interest via these parameters.

(start = -1) [real*4]

The start time for the observation. Start time defaults to the value in the pha file.

(stop = -1) [real*4]

The stop time for the observation. Stop time defaults to the value in the pha file.

(y_source = 0.0) [real*4]

The Y component of the source's unit vector in spacecraft coordinates. This value is used to calculate the response when 'NONE' is specified for the XTE attitude file, and the user wishes to specify the source position relative to the spacecraft X-axis. The default value is the nominal RXTE boresight ("sweet spot") used for most pointed RXTE observations.

(z_source = 0.0007) [real*4]

The Z component of the source's unit vector in spacecraft coordinates. This value is used to calculate the response when 'NONE' is specified for the XTE attitude file, and the user wishes to specify the source position relative to the spacecraft X-axis. The default value is the nominal RXTE boresight ("sweet spot") used for most pointed RXTE observations.

(chatter = 10) [integer]

The standard chatter parameter for how much to tell the user.

(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. This will create the arf file spec_pwa0.arf for the input pha file spec_pwa0.pha using the detector-axis ARF hexte_pwa0.arf. The XTE quaternion file for the observation (FH0e_2e89a5c-2e90abf) is given. The caldb will be searched for the collimator cube appropriate for HEXTE detector PWA0.

     hxtarf spec_pwa0.pha hexte_pwa0.arf spec_pwa0.arf FH0e_2e89a5c-2e90abf
               CALDB PWA0

NOTES:

BUGS

hxtarf_V1.*.

Cannot correctly handle large changes in spacecraft pointing

Does not have the facility to weight the collimator response by

the detector's livetime during the observation.

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

SEE ALSO

xpcaarf

CATEGORY