GCN Circular 5974
Subject
GRB 061222B, Swift-BAT refined analysis
Date
2006-12-22T20:38:24Z (17 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
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), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), J. L. Racusin (PSU), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-239.0 to T+903.1 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 061222 (trigger #252593)
(Racusin, et al., GCN Circ. 5957). The BAT ground-calculated position
is RA, Dec = 105.352, -25.865 deg which is
RA(J2000) = 7h 1m 24.6s
Dec(J2000) = -25d 51' 55.6"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 16%.
The burst had a single gradual peak with several sub peaks.
T90 (15-350 keV) is 40 +- 5 sec (estimated error including systematics).
At this time, there is a gap in the downlinked data from T+480 sec to
T+660 and T+720 to T+840 sec. A further Circular will be issued if
burst activity is found in these intervals.
The time-averaged spectrum from T+35.1 to T+84.3 is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 1.98 +- 0.13. The fluence in the 15-150 keV band is
2.2 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+59.16 sec in the 15-150 keV band is 1.5 +- 0.4 ph/cm2/sec. All the
quoted errors are at the 90% confidence level.