[vsnet-grb-info 2164] GRB 050916: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4003
SUBJECT: GRB 050916: Swift-BAT refined analysis
DATE:    05/09/19 16:16:05 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc at milkyway.gsfc.nasa.gov>

E. Fenimore (LANL), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/NRC), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), J. Nousek (PSU),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC),
G. Sato (ISAS), M. Tripicco (GSFC-SSAI), J. Tueller (GSFC),
on behalf of the Swift-BAT team:

Using the complete data set from T-300 to T+300 sec, we report further
analysis of Swift-BAT GRB 050916 (trigger #155408)  (Morris, et al.,
GCN 3991).  The refined BAT ground position is (RA,Dec) = 136.005, -51.411
{09h 04m 01.1s,-51d 24' 39"} [deg; J2000] +- 1.8 arcmin, (radius, sys+stat,
90% containment).  This is 1.4 arcmin from the XRT refined position reported
by Morris et al. (GCN 3996), The partial coding was 41%. 

The light curve shows a broad peak from T+0 to T+66 and a second weaker
peak from T+80 to T+100.  T90 (15-150 keV) is (90 +- 10) sec (estimated
error including systematics).

The power law index of the time-averaged spectrum is 1.83 +- 0.32.  The
fluence in the 15-150 keV band is (1.1 +- 0.4) x 10^-6 erg/cm^2.  The
1-sec peak photon flux measured from T+44 sec in the 15-150 keV band is
(0.66 +- 0.23) ph/cm2/sec.  All the quoted errors are at the 90%
confidence level.