GCN Circular 31899
Subject
GRB 220412A: Swift-BAT refined analysis
Date
2022-04-13T21:01:24Z (3 years ago)
From
Tyler Parsotan at UMBC/GSFC/CRESST II <parsotat@umbc.edu>
T. Parsotan (GSFC/UMBC), 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-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 220412A (trigger #1102281)
(Klingler et al. GCN Circ. 31881). The BAT ground-calculated position is
RA, Dec = 123.975, 30.336 deg which is
RA(J2000) = 08h 15m 54.0s
Dec(J2000) = +30d 20' 08.5"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.
The BAT light curve showed a complex
structure with a duration of about 20 sec. The peak count rate
was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger.
T90 (15-350 keV) is 41.66 +- 7.00 sec (estimated error including systematics).
The time-averaged spectrum from T-11.07 to T+38.00 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.53 +- 0.21. The fluence in the 15-150 keV band is 5.9 +- 0.9 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+6.88 sec in the 15-150 keV band
is 0.5 +- 0.1 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/1102281/BA/