GCN Circular 13096
Subject
GRB 120324A: Swift-BAT refined analysis
Date
2012-03-24T14:25:10Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC),
T. N. Ukwatta (MSU), B.-B. Zhang (PSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120324A (trigger #518507)
(Zhang, et al., GCN Circ. 13090). The BAT ground-calculated position is
RA, Dec = 291.081, 24.140 deg, which is
RA(J2000) = 19h 24m 19.5s
Dec(J2000) = +24d 08' 23.6"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.
The mask-weighted light curve shows many overlapping peaks starting
at ~T-190 sec with a weak precursor peak, the main peak at ~T+33 sec, and
ending at ~T+180 sec (and possible as long as ~T+330 sec at the 2-sigma level).
T90 (15-350 keV) is 118 +- 10 sec (estimated error including systematics).
The time-averaged spectrum from T-150.5 to T+142.5 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.34 +- 0.04. The fluence in the 15-150 keV band is 1.01 +- 0.03 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+33.68 sec in the 15-150 keV band
is 5.9 +- 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/518507/BA/