[vsnet-grb-info 3561] GRB 060804: Refined analysis of the Swift-BAT burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5395
SUBJECT: GRB 060804:  Refined analysis of the Swift-BAT burst
DATE:    06/08/04 18:00:12 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/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (GSFC/UMD),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
H. Z. Ziaeepour (UCL-MSSL)
on behalf of the Swift-BAT team:

Using the data set from T-240 to T+800 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 060804 (trigger #222546)
(Ziaeepour, et al., GCN Circ. 5394).  The BAT ground-calculated position
is RA,Dec = 112.216, -27.228 deg {7h 28m 51.8s, -27d 13' 41.8"} (J2000)
+- 2.1 arcmin, (radius, sys+stat, 90% containment).  The partial coding was 18%.
 
The mask-weighted lightcurve shows two overlapping peaks.  The first starts
at T-14 sec and peaking at T-10 sec. The second peaks at T+4 sec.
T90 (15-350 keV) is 16 +- 2 sec (estimated error including systematics).
 
The time-averaged spectrum from T-12.3 to T+5.5 is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum
is 1.78 +- 0.28.  The fluence in the 15-150 keV band is
5.1 +- 0.9 x 10^-7 erg/cm2.  The 1-sec peak photon flux measured
from T+4.46 sec in the 15-150 keV band is 1.2 +- 0.3 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.