GCN Circular 13220
Subject
GRB 120404A: Swift-BAT refined analysis
Date
2012-04-05T00:40:32Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (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),
G. Stratta (ASDC), J. Tueller (GSFC)
(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 120404A (trigger #519380)
(Strata, et al., GCN Circ. 13208). The BAT ground-calculated position is
RA, Dec = 235.002, 12.883 deg, which is
RA(J2000) = 15h 40m 00.4s
Dec(J2000) = +12d 52' 57.3"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 49%.
The mask-weighted light curve shows several overlapping peaks starting
at ~T-20 sec, peaking at ~T+4 sec, and ending at ~T+80 sec.
T90 (15-350 keV) is 38.7 +- 4.1 sec (estimated error including systematics).
The time-averaged spectrum from T-7.31 to T+38.45 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.85 +- 0.13. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.29 sec in the 15-150 keV band
is 1.2 +- 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/519380/BA/