niexposum - display NICER per-detector exposure


niexposum mkfile outfile [gtifile=file.gti[1]] [selcol=FPM_ON]


The niexposum task displays the approximate exposure time for each NICER detector module (FPM). This is useful for response calculation, and also for diagnosing detector on- and off- times.

The task uses the NICER filter file (.mkf file), which contains information on the FPM on-time on a per module basis. It can also use a NICER FPM selection file (with selcol=FPM_SEL).

The output file is an ASCII text file listing for each line, a detector and a total exposure per detector in seconds. This file would be suitable as NICER response file weights using the (detlist=@filename.lis parmeter).

By default, niexposum computes the per-detector on-times for the entire filter file. This is often not what is desired. Instead the user should specify a time selection file as a GTI file using the gtifile parameter. Typically this would be the GTI produced when extracting a NICER spectrum. For example, niexposum would be a suitable way to determine which detectors were enabled and for how much exposure during the spectrum myspectrum.pha, as follows,

  niexposum niNNNNNNNNNN.mkf detlist.lis gtifile="myspectrum.pha[GTI]"
Here niNNNNNNNNNN.mkf is the name of the filter file, and the output file detlist.lis will contain the textual list of exposures.


infile [string]
Name of filter file, or FPM selection file, with optional extension name.
outfile [filename]
Name of output ASCII listing
(gtifile=NONE) [string]
Name of time selection file and extension, or NONE. Typically this will be the GTI extension of the spectrum of interest (e.g. myspectrum.pha[GTI]). The extension name is required.
(selcol="INDEF") [string]
Column to use in the filter file or FPM Selection file. A value of "INDEF" (the default) will determine which column automatically based upon the contents of INFILE. If manual operation is required, set selcol=FPM_ON for a filter file and selcol=FPM_SEL for a FPM Selection file.
(cleanup="YES") [boolean]
If yes, then clean up temporary files. If no, temporary files remain. This is typically for debugging.
(clobber = NO) [boolean]
If the output file already exists, then setting "clobber = yes" will cause it to be overwritten.
(chatter = 2) [integer, 0 - 5]
Controls the amount of informative text written to standard output. Setting chatter = 4 or higher will produce detailed diagnostic output; chatter = 1 prints out a basic diagnostic message. The default is to produce a brief summary on output.
(history = YES) [boolean]
If history = YES, then a set of HISTORY keywords will be written to the header of the specified HDU in the output file to record the value of all the niexposum task parameters that were used to produce the output file.


See above.






Mar 2021