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GCN Circular 35303

GRB 231205B: Swift-BAT refined analysis
2023-12-07T14:01:00Z (7 months ago)
Tyler Parsotan at NASA GSFC <>
T. Parsotan (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. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231205B (trigger #1200812)
(Evans, et al., GCN Circ. 35269). The BAT ground-calculated position is
RA, Dec = 54.151, 27.150 deg which is
RA(J2000) = 03h 36m 36.3s
Dec(J2000) = +27d 09' 00.7"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.

The mask-weighted light curve shows a strong peak near the time of trigger.
There is also emission prior to the main peak of the lightcurve at ~T-30 sec.
T90 (15-350 keV) is 46.94 +- 7.84 sec (estimated error including systematics).

The time-averaged spectrum from T-29.66 to T+54.16 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.38 +- 0.05. The fluence in the 15-150 keV band is 7.4 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T-5.04 sec in the 15-150 keV band
is 7.1 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence

The results of the batgrbproduct analysis are available at <> <> <;>

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