TITLE:   GCN CIRCULAR
NUMBER:  35152
SUBJECT: GRB 231117A: Swift-BAT refined analysis
DATE:    23/11/21 19:58:25 GMT
FROM:    Tyler Parsotan  at NASA GSFC <tyler.parsotan@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), M. J. Moss (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231117A (trigger #1197027)
(Laha, et al., GCN Circ. 35071).  The BAT ground-calculated position is
RA, Dec = 332.404, 13.516 deg which is
   RA(J2000)  =  22h 09m 37.0s
   Dec(J2000) = +13d 30' 58.1"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.

The mask-weighted light curve shows a very strong fast rise exponential decay profile
with potential precursor emission prior to the main pulse.
T90 (15-350 keV) is 0.67 +- 0.07 sec (estimated error including systematics).

The time-averaged spectrum from T-0.42 to T+1.30 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.55 +- 0.04.  The fluence in the 15-150 keV band is 2.3 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-0.05 sec in the 15-150 keV band
is 28.9 +- 0.7 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/1197027/BA/