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GCN Circular 35033

Subject
GRB 231111A: Swift-BAT refined analysis
Date
2023-11-15T00:21:53Z (5 months ago)
From
Mike Moss at NASA GSFC <mikejmoss3@gmail.com>
Via
Web form
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
C. B. Markwardt (GSFC), A. Melandri (INAF-OAR),
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-239 to T+200 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231111A (trigger #1195887)
(Melandri, et al., GCN Circ. 34981).  The BAT ground-calculated position is
RA, Dec = 290.197, 52.440 deg which is
   RA(J2000)  =  19h 20m 47.3s
   Dec(J2000) = +52d 26' 22.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.
 
The BAT light curve shows a FRED-pulse structure peaking ~0 seconds after the trigger time.
T90 (15-350 keV) is 34.08 +- 4.88 sec (estimated error including systematics).
 
The time-averaged spectrum from T-5.32 to T+40.06 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.58 +- 0.07.  The fluence in the 15-150 keV band is 3.4 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+0.07 sec in the 15-150 keV band
is 2.7 +- 0.3 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/1195887/BA/
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