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GCN Circular 15049

Subject

GRB 130727A: Swift-BAT refined analysis

Date

2013-07-27T19:42:16Z (11 years ago)

From

Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>

W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), M. C. Stroh (PSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+831 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130727A (trigger #564342)
(Strohe, et al., GCN Circ. 15046Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 330.790, -65.540 deg, which is 
   RA(J2000)  =  22h 03m 09.5s 
   Dec(J2000) = -65d 32' 23.3" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
 
The mask-weighted light curve shows several overlapping peaks starting
at ~T-5 sec and ening at ~T+30 sec.  T90 (15-350 keV) is 13.57 +- 0.81 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-1.08 to T+24.38 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.65 +- 0.05.  The fluence in the 15-150 keV band is 3.8 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.42 sec in the 15-150 keV band
is 7.0 +- 0.3 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/564342/BA/