[vsnet-grb-info 2180] GRB 050922B: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4019
SUBJECT: GRB 050922B: Swift-BAT refined analysis
DATE:    05/09/23 00:03:15 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori at milkyway.gsfc.nasa.gov>

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

Using the data set from T-120 to T+450 sec from the recent telemetry
downlink, we report further analysis of Swift-BAT GRB 050922B
(trigger #156434)  (Norris, et al., GCN 4008).  The refined BAT ground 
position is (RA,Dec) = 5.789, -5.602 {00:23:09,-05:36:08} [deg; J2000]
+-2.3 arcmin, (radius, sys+stat, 90% containment).  The partial coding 
was 12%.  

The light curve shows a broad peak from T+15 to T+65 and a second peak 
from T+80 to T+110.  There is no extended emission T>120 sec.  
T90 (15-350 keV) is (80 +- 10) sec (estimated error including systematics).  

The power law index of the time-averaged spectrum is 1.89 +- 0.23.  
The fluence in the 15-150 keV band is (1.8 +- 0.3) x 10^-6 erg/cm2.  
The 1-sec peak photon flux measured from T0+98 sec in the 15-150 keV 
band is (1.1 +- 0.4) ph/cm2/sec.  All the quoted errors are at the 90% 
confidence level.