GCN Circular 35474
Subject
GRB 231230A: Swift-BAT refined analysis
Date
2024-01-03T14:07:21Z (4 months ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
Via
email
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), 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+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231230A (trigger #1205319)
(Moss, et al., GCN Circ. 35436). The BAT ground-calculated position is
RA, Dec = 245.223, 58.132 deg which is
RA(J2000) = 16h 20m 53.5s
Dec(J2000) = +58d 07' 54.2"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
The mask-weighted light curve shows a complex structure extending from
around T+0 to T+20. T90 (15-350 keV) is 15.2 +- 0.9 sec (estimated error including systematics).
The time-averaged spectrum from T+0.26 to T+17.26 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.28 +- 0.10. The fluence in the 15-150 keV band is 2.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.64 sec in the 15-150 keV band
is 2.2 +- 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/1205319/BA/