[vsnet-grb-info 3014] GRB 060306: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4851
SUBJECT: GRB 060306: Swift-BAT refined analysis
DATE:    06/03/06 17:15:50 GMT
FROM:    Hans Krimm at NASA-GSFC  <krimm at milkyway.gsfc.nasa.gov>

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

Using the data set from T-300 to T+300 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060306 (trigger
#200638) (Angelini, et al., GCN 4848).  The BAT ground-calculated
position is (RA,Dec) = 41.096, -2.155 deg {2h 44m 23.0s, -2d 9' 19.3"} (J2000)
+- 1.0 arcmin, (radius, sys+stat, 90% containment).  The partial
coding was 50%.

The light curve is a series of FRED-like peaks at T-1, T+1, T+27, T+43,
and T+60, with similar decay constants of ~2 sec.  The dominant peak is
at T+1.  The small  peak at T+60 is soft compared to the others, which all
have similar spectra.  T90 (15-350 keV) is 61 +- 2 sec (estimated error
including systematics).

The time-averaged spectrum from T-1.4 to T+66.9 is well fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.85 +- 0.10.   The fluence in the 15-150 keV band is
2.2 +- 0.1 x 10^-06 erg/cm2.   The 1-sec peak photon flux measured
from T+0.20 sec in the 15-150 keV band is 6.1 +- 0.3 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.