GCN Circular 3407
Subject
GRB 050509a: Swift-BAT refined analysis
Date
2005-05-10T16:36:13Z (20 years ago)
From
Louis M Barbier at NASA/GSFC/Swift <lmb@cosmicra.gsfc.nasa.gov>
L. Barbier (GSFC), S. Barthelmy (GSFC), P. Boyd (GSFC-UMBC),
J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
T. Mitani (ISAS) D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama),
J. Tueller (GSFC), W. Voges (MPE)
on behalf of the Swift/BAT team:
At 01:46:28 UT Swift-BAT detected GRB 050509a (trigger=118707)
(GCN Circ 3379, C. Hurkett, et al.). The refined BAT ground position
is (RA,Dec) = 310.608,+54.059, [deg; J2000] {20:42:24; +54:00:14}
+- 0.45 arcmin, (95% containment). XRT found an uncatalogued
x-ray source 13 arcseconds from the BAT position (GCN Circ 3380,
J. Kennea, et al.) The coding was 100% in the FOV.
The 1-s maskweighted lightcurve shows two distinct peaks. T90 (15-350 keV)
is (11.6 +- 1.0) seconds (estimated error including systematics).
The photon index of the time-averaged spectrum is 2.1 +- 0.2.
The fluence in the 15-350 keV band is (4.6 +- 0.7) x 10^-7 erg/cm2.
The 1-s peak photon flux measured from T0+0.388 second in the 15-350 keV
band is (0.98 +- 0.13) ph/cm2/s. All the quoted errors are at the 90%
confidence level.