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GCN Circular 14942

Subject
GRB 130626A, Swift-BAT refined analysis
Date
2013-06-27T20:18:56Z (10 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), M. De Pasquale (UCL-MSSL), E. E. Fenimore (LANL),
N. Gehrels (GSFC), 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-119 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130626A (trigger #559075)
(De Pasquale, et al., GCN Circ. 14931).  The BAT ground-calculated position is
RA, Dec = 273.128, -9.525 deg which is
   RA(J2000)  =  18h 12m 30.6s
   Dec(J2000) = -09d 31' 29.9"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a double short-peaked structure at T~ 0 sec.
The second peak is slightly weaker than the first peak, and starts immediately
at the end of the first peak. Each peak lasts ~ 0.08 sec.
T90 (15-350 keV) is 0.16 +- 0.03 sec (estimated error including systematics).

The time-averaged spectrum from T-0.0 to T+0.2 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index -0.53 +- 1.39,
and Epeak of 74.5 +- 25.6 keV (chi squared 54.40 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 5.2 +- 0.8 x 10^-08 erg/cm2
and the 1-sec peak flux measured from T-0.41 sec in the 15-150 keV band is
0.9 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.30 +- 0.21 (chi squared 62.40 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/559075/BA/
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