GCN Circular 4486
Subject
GRB 060111: Swift-BAT Refined Analysis
Date
2006-01-11T20:16:06Z (18 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
G. Sato (ISAS), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
F. Marshall (GSFC), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/ORAU), A. Smale (NASA HQ), J. Tueller (GSFC),
on behalf of the Swift-BAT team:
Using the data set from T-299 to T+303.0 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060111 (trigger #176818)
(Zane, et al., GCN 4479). The BAT ground-calculated position is
(RA,Dec) = 276.195, 37.596 {18h 24m 47.3s, 37d 35' 44.1"} (deg; J2000)
+- 0.8 arcmin, (radius, sys+stat, 90% containment). The partial coding
was 98%.
The light curve is a single peak, rise slightly faster than its decay.
T90 (15-350 keV) is (13 +- 1) sec (estimated error including
systematics). There is a small bump of marginal significance in the
15-50 keV band at T+280, the time of the x-ray flare observed by the
XRT (GCN circ. #4481, Goad et al.).
The time-averaged spectrum from T-0.7 to T+14.7 is best fit by a
cut-off power law with an Epeak of (72 +14, -8) keV and a photon
index of 0.8 +- 0.3. The fluence in the 15-150 keV band is (1.18 +-
0.05) x 10^-06 erg/cm2. A simple power law also gives an acceptable
fit, with a photon index of 1.63 +/- 0.07 and a fluence of (1.25 +-
0.05) x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+4.3 sec in the 15-150 keV band is (1.72 +- 0.15) ph/cm2/sec. All
the quoted errors are at the 90% confidence level.