GRB 200115A: Swift-BAT refined analysis
Abstract
Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200115A (trigger #949361) (Page, et al., GCN Circ. 26771). The BAT ground-calculated position is RA, Dec = 56.453, 5.607 deg, which is RA(J2000) = 03h 45m 48.7s Dec(J2000) = +05d 36' 26.0" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 82%. The mask-weighted light curve starts before T-50 sec, picking up at T-30 sec, continued increasing until the peak at T+100 sec, a couple weak following peaks, and having weak and flat emission out past the end of data at T+240 sec. T90 (15-350 keV) is 158.4 +- 32.6 sec (estimated error including systematics). The time-averaged spectrum from T-40.29 to T+233.12 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.29 +- 0.24, and Epeak of 75.0 +- 17.5 keV (chi squared 40.88 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.0 +- 0.0 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+99.75 sec in the 15-150 keV band is 3.6 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.77 +- 0.06 (chi squared 53.76 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/949361/BA/
- Publication:
-
GRB Coordinates Network
- Pub Date:
- January 2020
- Bibcode:
- 2020GCN.26780....1L