Generate point spread function cube for a stacked analysis.
This tool generates a point spread function cube for a stacked analysis. A point spread function cube is a 4-dimensional cube spanned by Right Ascension or Galactic longitude, Declination or Galactic latitude, energy, and offset angle between true and measured arrival direction of a photon. The energy binning of the cube may be either linear, logarithmic, or custom defined using an input file.
ctpsfcube requires on input the event list or observation definition XML file that has been used in the generation of the counts cube using ctbin.
It is not recommended to use the counts cube for the point spread function cube definition, although this is formally possible by specifying the counts cube as incube parameter. This leads however to a large FITS file on output since the number of bins in the counts cube will be multiplied by the number of offset angle bins (typically 200). Since the point spread function varies only little over the field of view of the camera it is recommended to use a rather coarse spatial binning to keep the file size manageable (with a typical value of binsz=1.0).
ctpsfcube generates a point spread function cube FITS file comprising three extensions. The primary extension contains a 3-dimensional image that contains the point spread function values. The energy and offset angle dimensions of the point spread function cube are folded into the 3rd dimension of the FITS image. The next extension named EBOUNDS contains a binary table that defines the energy boundaries of the exposure cube. The last extension named DELTAS contains a binary table that defines the offset angles between true and measured arrival direction of the photon.
chatter = 0: no information will be logged
chatter = 1: only errors will be logged
chatter = 2: errors and actions will be logged
chatter = 3: report about the task execution
chatter = 4: detailed report about the task execution
