[vsnet-grb-info 13716] GRB 130725A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15031
SUBJECT: GRB 130725A, Swift-BAT refined analysis
DATE:    13/07/25 19:05:30 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm at nasa.gov>

T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
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), B.-B. Zhang (PSU/UAH)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+731 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 130725A (trigger #563980)
(Zhang, et al., GCN Circ. 15028).  The BAT ground-calculated position is
RA, Dec = 230.060, 0.624 deg which is
     RA(J2000)  =  15h 20m 14.4s
     Dec(J2000) = +00d 37' 26.8"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 39%.

The mask-weighted light curve shows a double-peaked structure lasting from
approximately T+0 to T+20 seconds.  This is followed by lower-level emission out
to ~T+100 seconds. The source went out of the field of view at ~T+450 seconds,
following a pre-planned slew. T90 (15-350 keV) is 101.8 +- 20.5 sec (estimated
error including systematics).

The time-averaged spectrum from T-9.83 to T+103.40 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.60 +- 0.30.  The fluence in the 15-150 keV band is 9.7 +- 1.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+3.11 sec in the 15-150 keV band
is 0.6 +- 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/563980/BA/