GCN Circular 34515
Subject
GRB 230818A: Swift-BAT refined analysis
Date
2023-08-21T19:26:51Z (9 months ago)
From
Tyler Parsotan at NASA GSFC <tyler.parsotan@nasa.gov>
Via
email
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), 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-60 to T+200 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230818A (trigger #1186032)
(Tohuvavohu, et al., GCN Circ. 34479). The BAT ground-calculated position is
RA, Dec = 285.888, 40.888 deg which is
RA(J2000) = 19h 03m 33.2s
Dec(J2000) = +40d 53' 16.5"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
The mask weighted light curve shows a single fast rise exponential decay peak.
T90 (15-350 keV) is 9.82 +- 1.25 sec (estimated error including systematics).
The time-averaged spectrum from T+0.07 to T+12.10 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.36 +- 0.10. The fluence in the 15-150 keV band is 1.9 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+1.59 sec in the 15-150 keV band
is 6.7 +- 0.5 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/1186032/BA/ <http://gcn.gsfc.nasa.gov/notices_s/1186032/BA/>