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

Appendix B
BAT FITS Keywords
B.1 Introduction
The BAT ground software operates on standard FITS data files. However, the software produces
— and requires — certain FITS keywords in order to operate properly. This appendix describes
the keywords used. It also describes the HDUCLASn keywords used to identify the contents of
data files.
B.1.1 Keywords Used
The BAT software uses FITS keywords to both document the analysis procedures used, and to
pass information to downstream tasks. This section lists those keywords, how they are created and
used, and by what tasks.
• ACOLAPP - a boolean keyword indicating whether the autocollimation correction has been
applied to the image plate scale. Set by: batfftimage. Used by: none.
• BACKAPP - a boolean keyword which indicates whether the BAT background has been
subtracted. This can mean some form of explicit subtraction, or automatic subtraction via
the mask-weighting/imaging approaches. Set by: batfftimage,batbinevt. Used by: batclean.
• BALAPP - a boolean keyword indicating whether fine-level balancing has been performed
on a detector image. Set by: batclean. Used by: NONE
• BAT {X,Y,Z}OBJ - floating point keywords which indicate where in the BAT field of
view the source is located. The coordinate system is the BAT coordinate system, and the
units are centimeters. Objects at at infinity are placed at 10 km. Set by: batmaskwtevt,
batmaskwtimg, batupdatephakw. Used by: batcelldetect, batdrmgen.
• BAT RA, BAT DEC - floating point keywords which indicate where on the sky the source
is located (celestial RA and Dec). Set by: batmaskwtevt, batmaskwtimg. Used by: NONE.
• CLEANLEV - an integer keyword indicating the number of iterations of cleaning have been
performed. Set by: batclean. Used by: batclean.
• DISTAPP - a boolean keyword indicating whether the image, mask weights, or source detection
results have been adjusted for non-linear image distortion effects. Set by: batcelldetect,
batwarpimg, batmaskwtevt, batmaskwtimg. Used by: batwarpimg, batcelldetect.
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