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

42 CHAPTER 5. BAT ANALYSIS PROCEDURES
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Describe the good time interval column names in the file gti.col.
START 1D s
STOP 1D s
Enter required keywords into the file gti.head
MJDREFI = 51910 / Swift reference epoch: days
MJDREFF = 0.00074287037 / Swift reference epoch: fractional days
TIMEZERO = 0.0 / Time offset value
TRIGTIME = 142921742.016 / Trigger time: ** Change for your burst! **
And create the relative time good time interval.
ftcreate gti.col gti.txt offset.gti headfile=gti.head extname=GTI
Finally, add the trigger mission elapsed time (TRIGTIME=142921742.016 for this particular
GRB) to make an absolute-time good time interval file.
ftcopy offset.gti’[1][col START=START+TRIGTIME;STOP=STOP+TRIGTIME]’ absolute.gti
You can use this good time interval file to extract the light curve values in your desired time
bin ranges:
batbinevt infile=sw00145675000bevshsp_uf.evt.gz outfile=mybins.lc outtype=LC \
timedel=1.0 timebinalg=g energybins=15-150 gtifile=absolute.gti \
detmask=../hk/sw00145675000bcbdq.hk.gz clobber=YES