| Analysis: We use a PERL script to call
CIAO dm (data model) tools which return background subtracted
counts in several energy bands. Input is the observation level 2 events
file (evt2). dmlist is called several times to
gather header information for bookkeeping, aimpoint, and target location,
with dmcoords used to convert between coordinate systems.
Several source regions are pre-defined based on off-axis distance. These
range from a circle of radius 50 pixels (for sources less than 400 pixels
off-axis) to a 100 X 130 pixel ellipse (sources greater than 1200 pixels
off-axis). Source regions are written in sky coordinates. Appropriate
background regions are the same size and shape as the source region
are selected by referring to the source chip coordinates so that the
background remains on-chip and streak-free. An IDL-generated plot
is included as a link in each observation row to inspect the regions
selected. Finally, dmextract is called
with several energy filters and the source and background regions
parameters. Net counts are read from the output FITS table and reported
on the following pages.
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