GCN Circular 15105
Subject
GRB 130816A, Swift-BAT refined analysis
Date
2013-08-17T00:56:28Z (11 years ago)
From
Tilan Ukwatta at MSU <tilan.ukwatta@gmail.com>
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), S. T. Holland (STScI),
H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
G. Sato (ISAS), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from
the recent telemetry downlink, we report further
analysis of BAT GRB 130816A (trigger #566545)
(Holland , et al., GCN Circ. 15097). The BAT
ground-calculated position is
RA, Dec = 197.093, -58.996 deg which is
RA(J2000) = 13h 08m 22.3s
Dec(J2000) = -58d 59' 46.8"
with an uncertainty of 2.6 arcmin, (radius, sys+stat,
90% containment). The partial coding was 35%.
BAT mask-weighted light curve shows a two-peak structure.
The first peak starts around T-28 sec and lasts for about
5 sec. The second peak starts around T-3 sec and ends
around T+3 sec. BAT triggered on the second peak
and the first peak may be considered as a precursor
to the burst. T90 (15-350 keV) is 29.97 +- 1.36 sec
(estimated error including systematics).
The time-averaged spectrum from T-28.06 to T+2.56 sec
is best fit by a simple power-law model. The power
law index of the time-averaged spectrum is
1.86 +- 0.34. The fluence in the 15-150 keV band
is 4.3 +- 1.0 x 10^-07 erg/cm2. The 1-sec peak photon
flux measured from T-0.04 sec in the 15-150 keV band
is 1.5 +- 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/566545/BA/