• do gtselect

gtselect

@events.txt

crab_region_filtered.fits

83.633221

22.014461

3

239557500

274117500

100

300000

105

RA and DEC are generated from gtephem with start time of 239557500;

radius of new search region is 3 degree;

observation period is 400 days started by 239557500 (MET);

energy range: 100 MeV – 300 GeV; maximun zenith angle value is 105 degree.

• do gtmktime

gtmktime

spacecraft.fits

(IN_SAA!=T && DATA_QUAL==1 && LAT_CONFIG==1 && ABS(ROCK_ANGLE)<52

yes

crab_region_filtered.fits

crab_gtmktime.fits

• after gtmktime, do barycentering time correction

gtbary

crab_gtmktime.fits

spacecraft.fits

crab_event_bary.fits

83.633221

22.014461

while time range of spacecraft.fits which is 239557417-494731078 covers selected time period.

• frequency search by python

no good chi_square.

1. observation period set to 30days and 400days, no good.
2. radius of search region in gtselect process set to 0.5 degree, no good.