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GCN Circular 13961

Subject
GRB 121108A, Swift-BAT refined analysis
Date
2012-11-09T14:24:40Z (12 years ago)
From
Tilan Ukwatta at MSU <tilan.ukwatta@gmail.com>
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC),
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 (AGU), 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 121108A (trigger #537921) (Ukwatta, et al., GCN Circ. 13952).
The BAT ground-calculated position is RA, Dec = 83.216, 54.520 deg
which is
   RA(J2000)  =  05h 32m 51.9s
   Dec(J2000) = +54d 31' 11.2"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 90%.

BAT light curve shows two multi-peak episodes. First one starts
at the trigger time and lasts for about 50 seconds and the
second weak episode starts around T+130 seconds and lasts for about
40 seconds. T90 (15-350 keV) is 89 +- 48 sec (estimated error
including systematics).

The time-averaged spectrum from T-0.15 to T+137.98 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 2.28 +- 0.20.  The fluence in the 15-150 keV band is
9.6 +- 1.2 x 10^-07 erg/cm2. The 1-sec peak photon flux measured
from T+43.18 sec in the 15-150 keV band is 1.6 +- 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/537921/BA/
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