[vsnet-grb-info 6888] GRB 081104: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8479
SUBJECT: GRB 081104: Swift-BAT refined analysis
DATE:    08/11/04 22:39:17 GMT
FROM:    Ann M. Parsons at NASA/GSFC/Swift  <Ann.M.Parsons at nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC),C. B. Markwardt (GSFC/UMD),
K. McLean (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 081104 (trigger #333666)
(Parsons, et al., GCN Circ. 8473).  The BAT ground-calculated position is
RA, Dec = 100.500, -54.722 deg which is
   RA(J2000)  =  06h 42m 00.0s
   Dec(J2000) = -54d 43' 17.4"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
 
The BAT mask-weighted light curve shows a single FRED peak.
T90 (15-350 keV) is 59.1 +- 13.9 sec (estimated error including
systematics).
 
The time-averaged spectrum from T-23.5 to T+51.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.00 +- 0.14.  The fluence in the 15-150 keV band is 2.0 +- 0.2 x 10^-06
erg/cm2.
The 1-sec peak photon flux measured from T+13.54 sec in the 15-150 keV band
is 1.0 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/333666/BA/