TITLE:   GCN CIRCULAR
NUMBER:  35141
SUBJECT: GRB 231118A: Swift-BAT refined analysis
DATE:    23/11/20 20:35:03 GMT
FROM:    Mike Moss at NASA GSFC <mikejmoss3@gmail.com>

M. J. Moss (GSFC), S. D. Barthelmy (GSFC), 
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (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-61 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231118A (trigger #1197311)
(Laha, et al., GCN Circ. 35101).  The BAT ground-calculated position is
RA, Dec = 4.840, -48.044 deg which is 
   RA(J2000)  =  00h 19m 21.7s 
   Dec(J2000) = -48d 02' 37.5" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.
 
The light curve shows a single pulse with similar rise and fall times.
There is also a dim tail extending 30 seconds after the main pulse.
T90 (15-350 keV) is 37.63 +- 8.89 sec (estimated error including systematics).
 
The time-averaged spectrum from T-6.84 to T+55.21 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.40 +- 0.07.  The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band
is 9.7 +- 0.5 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/1197311/BA/