batglobalgti retrieves global good or bad times for BAT science analysis. The BAT CALDB has a GTI file which contains a listing of all known good and bad science analysis times, include a quality indicator and a description of any issues. This GTI is meant to reflect any operational issues that affected the BAT science data quality which are not easily extractable from the filter file or other telemetry. The user is not excused from doing other routine quality filtering, for example for SAA or noisy detectors. Thus, this task is most useful for doing gross filtering of data at the observation level to remove times of known bad data.
The time intervals stored in the GTI file have QUALITY values assigned according to the following scale:
The user can choose which quality level to accept with the 'expr' parameter. The default value is 0 or 1.
The result is a standard GTI file that can be merged with other GTI files, or otherwise used to time filter time-ordered Swift data. This GTI file applies to the entire mission duration.
Please note: The time intervals in the output file are not necessarily "good." That depends on the quality level chosen (i.e. if one chooses expr="QUALITY >= 2" then only the bad time intervals will be selected).
1. Create a "good" time interval file from CALDB.
batglobalgti CALDB good.gti