TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4020
SUBJECT: GRB 050922C: Swift-BAT refined analysis
DATE:    05/09/23 00:37:09 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>

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

Using the data set from T-10 to T+60 sec from the recent telemetry
downlink, we report further analysis of Swift-BAT GRB 050922C 
(trigger #156467)  (Norris, et al., GCN 4013).  The refined BAT ground position
is (RA,Dec) = 317.381, -8.762 {21:09:32, -8:45:43} [deg; J2000]
+- 1.0 arcmin, (radius, sys+stat, 90% containment).  The partial coding 
was 53%.  

The light curve shows the intense broad peak starting from T-3 to T+3 with 
at least two sub-peaks on top.  T90 (15-350 keV) is (5 +- 1) sec 
(estimated error including systematics).  

The power law index of the time-averaged spectrum is 1.33 +- 0.06.  
The fluence in the 15-150 keV band is (1.7 +- 0.1) x 10^-6 erg/cm2.  
The 1-sec peak photon flux measured from T-0.02 sec in the 15-150 keV 
band is (7.5 +- 0.3) ph/cm2/sec.  All the quoted errors are at the 90% 
confidence level.