GCN Circular 31486
Subject
GRB 220117B: Swift-BAT refined analysis
Date
2022-01-18T15:36:36Z (2 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. Parsotan (GSFC/UMBC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
A. Melandri (INAF-OAB), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+717 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 220117B (trigger #1093611)
(Melandri et al., GCN Circ. 31468). The BAT ground-calculated position is
RA, Dec = 191.989, -28.762 deg which is
RA(J2000) = 12h 47m 57.3s
Dec(J2000) = -28d 45' 42.8"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.
The mask-weighted light curve shows a weak structure that starts
at ~T-3 s and ends at ~T+23 s. T90 (15-350 keV) is 24.37 +- 4.63 sec
(estimated error including systematics).
The time-averaged spectrum from T-2.73 to T+23.29 sec is best fit
by a simple power-law model. The power law index of the time-averaged
spectrum is 1.94 +- 0.32. The fluence in the 15-150 keV band is
2.9 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from
T-0.13 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec.
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/1093611/BA/