[vsnet-grb-info 3882] GRB 061007: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5713
SUBJECT: GRB 061007: Swift-BAT refined analysis
DATE:    06/10/07 23:25:05 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc at milkyway.gsfc.nasa.gov>

C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. D. Barthelmy (GSFC), 
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
P. Schady (MSSL-UCL), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
 
Using the data set from T-58 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 061007 (trigger #232683)  
(Schady, et al., GCN Circ. 5707).  The BAT ground-calculated position is 
RA,Dec = 46.299, -50.496 deg {3h 5m 11.8s, -50d 29' 47.4"} (J2000)
+- 0.9 arcmin, (radius, sys+stat, 90% containment).  The partial coding 
was 19%.  Before T-58 sec, the burst location was not in BAT's FOV,
but there is no detection through the side of the instrument of any
significant earlier emission.
 
The lightcurve shows three large peaks, each with several seconds rise
and fall and a roughly flat top, and each including several sub-peaks.
The first lasts from T-5 to T+15, the second from T+23 to T+40, and the
third from T+40 to T+65 sec.  There is a smaller peak starting at T+75, 
rising to a flat top from T+78 to T+80 and then declining with a very long
roughly exponential decay. Emission is weakly detectable until around
T+900 sec.  T90 (15-350 keV) is 75 +- 5 sec (estimated error including 
systematics).
 
The time-averaged spectrum from T-4.1 to T+231.8 is best fit by a simple 
power-law model.  The power law index of the time-averaged spectrum 
is 1.13 +- 0.03.  The fluence in the 15-150 keV band is 
4.5 +- 0.1 x 10^-05 erg/cm2.  The 1-sec peak photon flux measured from 
T+45.14 sec in the 15-150 keV band is 15.3 +- 0.4 ph/cm2/sec.  All the 
quoted errors are at the 90% confidence level.