[vsnet-grb-info 1876] GRB050730: Refined BAT analysis of the Swift-BAT burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3715
SUBJECT: GRB050730:  Refined BAT analysis of the Swift-BAT burst
DATE:    05/07/31 05:50:18 GMT
FROM:    Craig Markwardt at NASA/GSFC/UMD  <craigm at milkyway.gsfc.nasa.gov>

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

Using the full BAT data set from the recent telemetry downlink, we report
further analysis of Swift-BAT GRB 050730 (trigger #148225)
(Holland, et al., GCN 3704).  The ground-analysis position is
RA,Dec 212.063,-3.740 (J2000) with an uncertainty of 3 arcmin
(radius, 90%, stat+sys).  The light curve shows a gradual increase
in emission starting at T-60 sec with a peak at T+10 sec
and then a gradual decline out to T+120 sec.  T90 is 155 +- 20 sec.
Fitting a simple power law over the full interval from T-60 to T+120 seconds,
the photon index is 1.5 +/- 0.1 with a fluence of 4.4 +/- 0.4 X 10^-6 erg/cm^2
in the 15-350 keV band (90% c.l.).  The peak flux in a 1-sec wide window
starting at T+4.8 seconds is 0.74 +/- 0.17 ph/cm^2/sec (15-350 keV).