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GCN Circular 12504

Subject
GRB 111029A: Swift-BAT refined analysis
Date
2011-10-29T16:11:50Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU),
E. Troja (NASA/GSFC/ORAU), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 111029A (trigger #506519)
(Troja, et al., GCN Circ. 12498).  The BAT ground-calculated position is
RA, Dec = 44.785, 57.101 deg, which is 
   RA(J2000)  =  02h 59m 08.4s 
   Dec(J2000) = +57d 06' 02.9" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 75%.
 
The mask-weighted light curve shows 2 or 3 overlapping peaks starting
at ~T+15 and ending at ~T=35 sec.  T90 (15-350 keV) is 7.6 +- 1.1 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+19.60 to T+28.92 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.77 +- 0.71, 
and Epeak of 36.2 +- 5.7 keV (chi squared 39.5 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 3.9 +- 0.4 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T+23.62 sec in the 15-150 keV band is
1.5 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.11 +- 0.13 (chi squared 53.6 for 57 d.o.f.).  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/506519/BA/
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