GCN Circular 22153
Subject
GRB 171123A: Swift-BAT refined analysis
Date
2017-11-24T00:14:52Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. A. Evans (U Leicester),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), 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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 171123A (trigger #791922)
(Evans et al., GCN Circ. 22148). The BAT ground-calculated position is
RA, Dec = 186.198, 32.503 deg which is
RA(J2000) = 12h 24m 47.6s
Dec(J2000) = +32d 30' 12.5"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 86%.
The mask-weighted light curve shows a weak pulse that starts at ~T-1 s and ends
at ~T+20 s, with a tail lasting till ~T+60 s. In addition, there is a weak
precursor from ~T-25 s to ~T-20 s. T90 (15-350 keV) is 58.5 +- 27.1 sec
(estimated error including systematics).
The time-averaged spectrum from T-1.39 to T+60.29 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.35 +- 0.34. The fluence in the 15-150 keV band is 4.8 +- 1.0 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.27 sec in the 15-150 keV band
is 0.8 +- 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/791922/BA/