The SWIFT BAT Software Guide Version 6.3 30 ... - HEASARC - Nasa

D.15. BATMASKWTIMG 165
D.15 BATMASKWTIMG
D.15.1 NAME
batmaskwtimg - compute mask weights for the entire detector BAT plane
D.15.2 USAGE
batmaskwtimg outfile attitude ra dec
D.15.3 DESCRIPTION
batmaskwtimg constructs a mask weighting map, for a particular source position, for the entire
BAT detector plane. This is the first step to computing a flux or spectrum for a source from survey
type or image type data. The output is an image of the detector plane with one mask weight for
each detector.
Users can also compute a “forward” ray tracing map, which gives the expected counts in each
detector based on a unit intensity source, accounting for various geometric optics effects. Users
should use ”corrections=forward,unbalanced,flatfield“ and ”rebalance=no” in order to simulate
such a map.
Users can also request analysis for a batch of sources in a catalog, using the ‘incatalog’ parameter.
The catalog must provide at least the source position (and optionally the name of the
source and an identifying number). By default, the output will contain multiple extensions, one
for each source. However, individual catalog maps can be combined into one map with the combmeth
parameter. NOTE: If the input catalog is empty, then no output catalog will be created. If
‘clobber=yes’ is set and the input catalog is empty, then any pre-existing output file will be erased.
The actual output map type is controlled by the ‘outtype’ parameter. By default it is
WEIGHTS, indicating to output the ray traced mask weights. If outtype=ZERO or outtype=NONZERO
is chosen, then a “footprint” mask is made instead, which shows which parts
of the aperture (or non-aperture) illuminates the array, regardless of the aperture pattern. This
may be especially useful in combination with combmeth=“MIN” or “MAX”, to mask out portions
of the array illuminated by particular sources.
By default, the coordinates are right ascension and declination. Users must also provide the
instrument aperture and teldef files (or use CALDB). Instrument coordinates can also be used, as
described in ADVANCED COORDINATE SYSTEMS below.
D.15.4 ADVANCED COORDINATE SYSTEMS
Users may specify a source position using a coordinate system other than sky position. Depending
on the value of the coord type parameter, the user may give the cartesian or angular position
of the source in instrument coordinates. When coord type is changed from “sky” to any of the