GCN Circular 4820
Subject
GRB 060223: Swift-BAT refined analysis
Date
2006-02-23T19:34:30Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
J. Cummings (GSFC/NRC), S. Barthelmy (GSFC), L. Barbier (GSFC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the partial data set from T-300 to T+302 sec from telemetry
downlinks, we report further analysis of BAT GRB 060223 (trigger #192059)
(Cummings, et al., GCN 4813; Marshall et al, GCN 4814).
The BAT ground-calculated position is RA,Dec = 55.188,-17.130 deg
{3h 40m 45.1s, -17d 7' 46.6"} (J2000) +- 1.2 arcmin, (radius, sys+stat,
90% containment). The BAT error circle contains the afterglow detected
by UVOT (GCN 4813). The partial coding was 69%.
The mask-weighted light curve shows a single episode of emission
from T-4 to T+10 sec. There is a possible broad, faint precursor
at ~T-25 sec, but no significant emission after T+10 sec.
T90 (15-350 keV) is 11 +- 2 sec (estimated error including systematics).
The time-averaged spectrum from T-2.9 to T+10.0 is best fit by a
simple power-law model. The power-law index of the time-averaged
spectrum is 1.74 +- 0.12. The fluence in the 15-150 keV band is
6.8 +- 0.5 x 10^-07 erg/cm2. The 1-sec peak photon flux measured
from T+0.08 sec in the 15-150 keV band is 1.4 +- 0.2 ph/cm2/sec.
All the quoted errors are at the 90% confidence level. Given the redshift
reported for this burst (Berger et al, GCN 4815), z = 4.41, we calculate
Eiso = 2.82 10^52 ergs in the 81-812 keV band in the rest frame of the
source.