[vsnet-grb-info 4449] GRB 070328, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6225
SUBJECT: GRB 070328, Swift-BAT refined analysis
DATE:    07/03/28 07:49:48 GMT
FROM:    Craig Markwardt at NASA/GSFC/UMD  <craigm at milkyway.gsfc.nasa.gov>

M. Stamatikos (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), 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 (GSFC/ISAS),
J. Tueller (GSFC)
on behalf of the Swift-BAT team:
 
Using the data set from T-120 to T+183 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 070328 (trigger
#272773) (Markwardt et al., GCN Circ. 6224).  The BAT
ground-calculated position is RA, Dec = 65.110, -34.077 deg which is
   RA(J2000) = 4h 20m 26.4s 
   Dec(J2000) = -34d 4' 38.9" 
with an uncertainty of 0.6 arcmin, (radius, sys+stat, 90%
containment).  The partial coding was 60%.

The mask weighted light curve shows a burst profile which consists
of a rise starting at T-10, multiple spikes peaking between T+0
and T+22, and a gradual decay detected out to T+140.  T90 (15-350 keV)
is 69 +- 5 sec (estimated error including systematics).
 
The time-averaged spectrum from T-8.5 to T+133 is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.26 +- 0.04.  The fluence in the 15-150 keV band is 8.9 +- 0.2 x
10^-6 erg/cm2.  The 1-sec peak photon flux measured from T+0.78 sec in
the 15-150 keV band is 4.2 +- 0.2 ph/cm2/sec.  All the quoted errors
are at the 90% confidence level.