GRB 210308A: 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 210308A (trigger #1036227) (D'Elia, et al., GCN Circ. 29619). The BAT ground-calculated position is RA, Dec = 67.083, 37.429 deg which is RA(J2000) = 04h 28m 19.9s Dec(J2000) = +37d 25' 42.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 32%. The mask-weighted light curve shows a double-peaked structure from T-0.5 sec to T+9 sec. The first pulse peaks at T+0.2 sec, and the second pulse peaks at T+3 sec. T90 (15-350 keV) is 5.3 +- 0.6 sec (estimated error including systematics). The time-averaged spectrum from T-0.04 to T+7.36 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.76 +- 0.28, and Epeak of 113.6 +- 31.0 keV (chi squared 52.89 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.2 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+2.12 sec in the 15-150 keV band is 13.6 +- 0.7 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.38 +- 0.06 (chi squared 69.63 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/1036227/BA/
- Publication:
-
GRB Coordinates Network
- Pub Date:
- March 2021
- Bibcode:
- 2021GCN.29633....1P