GRB 180626A: Swift-BAT refined analysis
Abstract
Using the data set from T-239 to T+526 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180626A (trigger #844615) (Evans, et al., GCN Circ. 22850). The BAT ground-calculated position is RA, Dec = 243.569, 14.759 deg which is RA(J2000) = 16h 14m 16.6s Dec(J2000) = +14d 45' 32.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a multi-peaked structure. The first peak is from approximately T-10 to T+5 sec, with a second overlapping peak from T+5 to T+20 sec, followed by a weaker peak from T+20 to T+30 sec. T90 (15-350 keV) is 30.07 +- 1.42 sec (estimated error including systematics). The time-averaged spectrum from T-10.01 to T+25.59 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.64 +- 0.27, and Epeak of 47.7 +- 12.2 keV (chi squared 40.18 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 4.8 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T-3.69 sec in the 15-150 keV band is 4.1 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.01 +- 0.06 (chi squared 46.26 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/844615/BA/
- Publication:
-
GRB Coordinates Network
- Pub Date:
- June 2018
- Bibcode:
- 2018GCN.22862....1K