TITLE:   GCN CIRCULAR
NUMBER:  34914
SUBJECT: GRB 231028A: Swift-BAT refined analysis
DATE:    23/10/30 17:03:43 GMT
FROM:    Tyler Parsotan  at NASA GSFC <tyler.parsotan@nasa.gov>

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
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-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231028A (trigger #1193078)
(Williams et al., GCN Circ. 34894).  The BAT ground-calculated position is
RA, Dec = 214.016, 20.897 deg which is
   RA(J2000)  =  14h 16m 03.8s
   Dec(J2000) = +20d 53' 47.8"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 68%.

The mask-weighted lightcurve shows a broad initial pulse with subsequent
extended emission.
T90 (15-350 keV) is 37.23 +- 0.98 sec (estimated error including systematics).

The time-averaged spectrum from T-6.86 to T+41.95 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.40 +- 0.04.  The fluence in the 15-150 keV band is 7.2 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+1.06 sec in the 15-150 keV band
is 8.6 +- 0.4 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/1193078/BA/