[vsnet-grb-info 15479] GRB 140903A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16768
SUBJECT: GRB 140903A: Swift-BAT refined analysis
DATE:    14/09/04 01:33:48 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings at nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),  W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings, N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
  
Using the data set from T-61 to T+159 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 140903A (trigger #611599)
(Cummings, et al., GCN Circ. 16763).  The BAT ground-calculated position is
RA, Dec = 238.021, 27.608 deg which is
    RA(J2000)  =  15h 52m 05.0s
    Dec(J2000) = +27d 36' 27.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.
  
The mask-weighted light curve shows a single FRED peak.  T90 (15-350 keV) is
0.30 +- 0.03 sec (estimated error including systematics).
  
The time-averaged spectrum from T-0.01 to T+0.35 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.99 +- 0.12.  The fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T-0.33 sec in the 15-150 keV band
is 2.5 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

This burst was short but we note that it was not particularly hard.
  
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/611599/BA/