GCN Circular 33519
Subject
GRB 230322B: Swift-BAT refined analysis
Date
2023-03-25T17:01:17Z (a year ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), H. A. Krimm (NSF),
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-826 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 230322B (trigger #1161127)
(Cenko et al., GCN Circ. 33505). The BAT ground-calculated position is
RA, Dec = 16.550, -47.709 deg which is
RA(J2000) = 01h 06m 12.1s
Dec(J2000) = -47d 42' 31.2"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.
The mask-weighted light curve shows a single-peaked FRED-like structure
that starts at ~T-3 s, peaks at ~T0, and ends at ~T+11 s.
T90 (15-350 keV) is 11.61 +- 2.17 sec (estimated error including
systematics).
The time-averaged spectrum from T-2.41 to T+11.12 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
2.07 +- 0.26. The fluence in the 15-150 keV band is 3.7 +- 0.6 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+0.02 sec in the 15-150 keV band
is 1.1 +- 0.2 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/1161127/BA/