[vsnet-grb-info 20058] GRB 171123A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22153
SUBJECT: GRB 171123A: Swift-BAT refined analysis
DATE:    17/11/24 00:14:52 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at 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/