The region task takes a FITS-table list of source positions (which must be RA and dec in decimal degrees) as input and creates one or more FITS-format region tables as output. The spatial regions which the task writes to output are intended to be used to filter the original event list for the exposure in question so as to isolate those events corresponding to either (i) a single source in the input source list; (ii) the local background around such a source; or (iii) the `global' background consisting of all events sufficiently far from all sources in the input list.
The region tables which the task creates conform to the ASC region specification [1].
