[vsnet-grb-info 6212] GRB 080605, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7841
SUBJECT: GRB 080605, Swift-BAT refined analysis
DATE:    08/06/06 17:44:56 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), J. Tueller (GSFC),
T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 080605 (trigger #313299)
(Sbarufatti, et al., GCN Circ. 7828).  The BAT ground-calculated position is
RA, Dec = 262.130, 4.010 deg, which is 
   RA(J2000)  =  17h 28m 31.1s 
   Dec(J2000) = +04d 00' 35.6" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.
 
The mask-weighted light curve shows a cluster of overlapping peaks
starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec.
At the 1-2 sigma level, there is appears to be persistant emmission
in the T+300 to T+700 sec range.  T90 (15-350 keV) is 20 +- 1 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.11 +- 0.14, 
and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.).   For this
model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is
19.9 +- 0.6 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.36 +- 0.03 (chi squared 37 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/313299/BA/