GRB 220101A: Swift-BAT refined analysis
Abstract
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220101A (trigger #1091527) (Tohuvavohu et al. GCN 31347). The BAT ground-calculated position is RA, Dec = 1.360, 31.758 deg which is RA(J2000) = 00h 05m 26.4s Dec(J2000) = +31d 45' 28.3" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%. The BAT lightcurve shows a complex lightcurve extending to at least T+170 with a peak of 7000 counts/s (15-350 keV), at ~89 sec after the trigger. T90 (15-350 keV) is 173.36 +- 12.76 sec (estimated error including systematics). The time-averaged spectrum from T-58.08 to T+259.11 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.13 +- 0.13, and Epeak of 249.1 +- 161.8 keV (chi squared 42.49 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.5 +- 0.0 x 10^-05 erg/cm2 and the 1-sec peak flux measured from T+89.07 sec in the 15-150 keV band is 7.3 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.34 +- 0.03 (chi squared 50.91 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/1091527/BA/
- Publication:
-
GRB Coordinates Network
- Pub Date:
- January 2022
- Bibcode:
- 2022GCN.31369....1M