TITLE:   GCN CIRCULAR
NUMBER:  34675
SUBJECT: GRB 230911C: Swift-BAT refined analysis
DATE:    23/09/12 03:07:59 GMT
FROM:    Amy <yarleen@gmail.com>

T. Sakamoto (AGU), 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),
E. Sonbas (Adiyaman Univ.), 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 230911C (trigger #1191188)
(Sonbas et al., GCN Circ. 34655).  The BAT ground-calculated position is
RA, Dec = 226.796, -41.356 deg which is
   RA(J2000)  =  15h 07m 11.0s
   Dec(J2000) = -41d 21' 21.2"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 95%.

The mask-weighted light curve shows multiple weak overlapping pulses that
start at ~T-9 s and end at ~T+10 s. T90 (15-350 keV) is 16.21 +- 2.89 sec
(estimated error including systematics).

The time-averaged spectrum from T-8.63 to T+9.58 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.26 +- 0.28.  The fluence in the 15-150 keV band is 3.8 +- 0.6 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+2.07 sec in the 15-150 keV band
is 0.7 +- 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/1191188/BA/