[vsnet-grb-info 3755] GRB 060923, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5589
SUBJECT: GRB 060923, Swift-BAT refined analysis
DATE:    06/09/23 10:28:17 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

J. Tueller (GSFC) L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU)
on behalf of the Swift-BAT team:
 
Using the data set from T-240 to T+879 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 060923 (trigger #230662)
(Stamatikos, et al., GCN Circ. 5583).  The BAT ground-calculated position
is RA,Dec = 254.623, 12.341 deg {16h 58m 29.6s, 12d 20' 28.1"} (J2000)
+- 2.1 arcmin, (radius, sys+stat, 90% containment).  The partial coding was 33%.
 
The burst started with a 6-sec wide peak at T-42 sec.  The main peak starts
at T-5 sec, peaks at T+1 sec, and ends at T+20 sec.  There is a possible
third peak at T+19 sec.  T90 (15-350 keV) is 51.7 +- 1 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-42.3 to T+11.5 is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.69 +- 0.23.  The fluence in the 15-150 keV band is 8.7 +- 1.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.03 sec in the 15-150 keV band
is 1.3 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence level.