[vsnet-grb-info 3255] GRB 060507: Swift-BAT Refined Analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5090
SUBJECT: GRB 060507: Swift-BAT Refined Analysis
DATE:    06/05/08 02:49:57 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

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

Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 060507 (trigger #208870)
(Barbier, et al., GCN 5089).  The BAT ground-calculated position is
RA,Dec = 89.935,+75.243 deg {5h 59m 44.3s,+75d 14' 36.1"} (J2000)
+- 5.0 arcmin, (radius, sys+stat, 90% containment).  The partial coding
was 33%.

The light curve shows an initial peak with a long decay, followed by
a series of smaller peaks between T+100 and T+200 seconds.
Currently, there are four gaps in the telemetry downlinked data
which prevent us from analyzing this burst between T-42 to T-10.3 sec,
T+78.4 to T+80.6, T+88.7 to T+98.6, and T+167.4 to T+170.6 sec.
T90 (15-350 keV) is 185 +- 5 sec (estimated error including systematics).
The very long duration and absence of short timescale spikes in the
lightcurve could be indicative of a high redshift event.

The time-averaged spectrum from T-10 to T+192 (minus the gaps listed above)
is best fit by a simple power-law model.  The power law index of the
time-averaged spectrum is 1.83 +- 0.09.  Because of the data gaps,
the lower limit on the fluence in the 15-150 keV band is
4.1 +- 0.2 x 10^-6 erg/cm2.  The 1-sec peak photon flux measured from
T+1.24 sec in the 15-150 keV band is 1.3 +- 0.2 ph/cm2/sec.  All the quoted
errors are at the 90% confidence level.