[vsnet-grb-info 2819] GRB 060203: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4656
SUBJECT: GRB 060203:  Swift-BAT refined analysis
DATE:    06/02/04 16:15:57 GMT
FROM:    Hans Krimm at NASA-GSFC  <krimm at milkyway.gsfc.nasa.gov>

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

Using the data set from T-299.0 to T+183.0 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060203 (trigger #180151)
(Retter et al., 4641, Burrows et al., GCN 4644, Cummings et al., GCN 4649).
The BAT ground-calculated position is (RA,Dec) = 103.502, 71.838  deg
{06h 54m 0.5s,+71d 50' 15.9"} (J2000) +- 1.9 arcmin, (radius, sys+stat,
90% containment).  The partial coding was 50%.

Based on the event data that we have, the mask-weighted light curve shows a
single broad peak lasting from T-20 to T+65 seconds.  T90 (15-350 keV) is
60 +- 10 sec (estimated error including systematics).  There is no evidence in
the rate data for emission after this peak. We note that according to the
flight log files, event data was cut off at T+183 seconds due to a
pre-planned slew.

The time-averaged spectrum from T-22.1 to T+45.7 is best fit by a simple
power-law model.   The power law index of the time-averaged spectrum is
1.62 +- 0.23.  The fluence in the 15-150 keV band is (8.5 +- 1.2) x
10^-07 erg/cm2.  The 1-sec peak photon flux measured from T+25.92 sec
in the 15-150 keV band is (0.6 +- 0.2) ph/cm2/sec.  All the quoted errors
are at the 90% confidence level.