GCN Circular 9915

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),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
E. Troja (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry 
downlink,
we report further analysis of the short BAT GRB 090916 (trigger #362818)
(Troja, et al., GCN Circ. 9913
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 126.582, 25.941 deg which is
  RA(J2000)  =  08h 26m 19.6s
  Dec(J2000) = +25d 56' 27.3"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 34%.

The mask-weighted light curve consisted of a single peak of 0.32 sec 
duration
starting at T-0.128 sec, followed by low-level emission extending out to 
about
T+70 sec. T90 (15-350 keV) is 63.4 +- 15.2 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.0 to T+68.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.42 +- 0.33.  The total fluence in the 15-150 keV band is
9.5 +- 1.8 x 10-7 erg/cm2. The peak second starting from T-0.036 sec is
best fit by a simple power-law model. The power law index of the peak-second
spectrum is 1.41 +- 0.28.  The 1-sec peak fluence in the 15-150 keV band is
1.5 +- 0.26 x 10-7 erg/cm2. The 1-sec peak photon flux in the
15-150 keV band is 1.9 +- 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/362818/BA/