GRB 050416b: Swift-BAT refined analysis

[RJN]

TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 3284
SUBJECT: GRB 050416b: Swift-BAT refined analysis
DATE: 05/04/17 03:26:08 GMT
FROM: Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>


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


At 22:35:54.1 UT Swift-BAT detected GRB 050416b (trigger=114797)
(GCN Circ 3279, Hullinger et al.). The refined BAT ground position
is (RA,Dec) = 133.854, 11.182, [deg; J2000] +- 3 arcmin, (95%
containment). The partial coding fraction was 16%.

The moon is moving towards the position of the GRB, and Swift will not
be able to observe for several days because of the spacecraft moon
angle constraint.


The BAT mask weighted light curve shows a FRED-like structure.
T90 (15-350 keV) is (5.4 +- 0.9) seconds (estimated error including
systematics).


The time-averaged spectrum is well fitted in a simple power-law
model. The photon index is 1.5 +- 0.2. The fluence in the 15-350
keV band is (2.1 +- 0.3) x 10^-6 erg/cm2. The peak photon flux in
the 15-350 band is (7.9 +- 0.7) ph/cm2/s. The quoted errors are at
the 90% confidence level.