GRB 220325A: 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 220325A (trigger #1099310) (Ferro et al., GCN Circ. 31787). The BAT ground-calculated position is RA, Dec = 269.469, -7.055 deg which is RA(J2000) = 17h 57m 52.7s Dec(J2000) = -07d 03' 18.4" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 52%. The BAT light curve showed a complex structure with a duration of about 6 sec. T90 (15-350 keV) is 3.50 +- 0.56 sec (estimated error including systematics). The time-averaged spectrum from T-0.97 to T+3.02 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.69 +- 1.13, and Epeak of 39.3 +- 8.9 keV (chi squared 63.15 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.9 +- 0.4 x 10^-07 erg/cm2 and the 1-sec peak flux measured from T+0.53 sec in the 15-150 keV band is 2.0 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.06 +- 0.17 (chi squared 69.80 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/1099310/BA/
- Publication:
-
GRB Coordinates Network
- Pub Date:
- March 2022
- Bibcode:
- 2022GCN.31799....1L