[vsnet-grb-info 13794] GRB 130816B, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15108
SUBJECT: GRB 130816B, Swift-BAT refined analysis
DATE:    13/08/17 16:08:14 GMT
FROM:    Tilan Ukwatta at MSU  <tilan.ukwatta at gmail.com>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), 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), T. Sakamoto (AGU),
G. Sato (ISAS), J. Tueller (GSFC),
T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from
the recent telemetry downlink, we report further
analysis of BAT GRB 130816B (trigger #566561)
(Stamatikos, et al., GCN Circ. 15099). The BAT
ground-calculated position is
RA, Dec = 170.049, -57.527 deg which is
   RA(J2000)  =  11h 20m 11.8s
   Dec(J2000) = -57d 31' 37.7"
with an uncertainty of 1.6 arcmin, (radius,
sys+stat, 90% containment).The partial
coding was 98%.

BAT mask-weighted light curve shows a single peak
starting from ~T-10 sec peaking around T+0 sec
and ending at ~T+4 sec. T90 (15-350 keV) is
10.00 +- 3.61 sec (estimated error including
systematics).

The time-averaged spectrum from T-6.50 to T+6.50 sec
is best fit by a power law with an exponential cutoff.
This fit gives a photon index 0.45 +- 0.93, and
Epeak of 47.3 +- 10.8 keV (chi squared 35.98 for
56 d.o.f.). For this model the total fluence in
the 15-150 keV band is 2.7 +- 0.4 x 10^-07 erg/cm2
and the 1-sec peak flux measured from T+0.50 sec
in the 15-150 keV band is 0.9 +- 0.1 ph/cm2/sec.
A fit to a simple power law gives a photon index
of 1.82 +- 0.17 (chi squared 44.98 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/566561/BA/