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GCN Circular 34379

Subject
GRB 230805B: Swift-BAT refined analysis
Date
2023-08-10T16:51:21Z (9 months ago)
From
Sibasish Laha at NASA-GSFC <slaha@umbc.edu>
Via
legacy email
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-40 to T+200 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 230805B (trigger #1183217)
(Cenko et al., GCN Circ. 34339).  The BAT ground-calculated position is
RA, Dec = 207.738, 31.190 deg which is
   RA(J2000)  =  13h 50m 57.2s
   Dec(J2000) = +31d 11' 23.0"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.

The BAT  light curve shows a complex structure with a duration of ~ 100 sec.
T90 (15-350 keV) is 93.77 +- 18.83 sec (estimated error including
systematics).

The time-averaged spectrum from T-21.60 to T+103.27 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.36 +- 0.20.  The fluence in the 15-150 keV band is 1.9 +- 0.2 x 10^-06
erg/cm2.
The 1-sec peak photon flux measured from T-17.66 sec in the 15-150 keV band
is 1.2 +- 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/1183217/BA/

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