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GCN Circular 2898

Subject
GRB041223: Swift-BAT detection of a bright long burst
Date
2004-12-23T17:58:52Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
J. Tueller, L. Barbier, S. Barthelmy (GSFC), A. Beardmore (U.Leicester),
L. Cominsky (Sonoma State U), J. Cummings (GSFC), E. Fenimore (LANL),
N. Gehrels (GSFC), S.T. Holland (GSFC/USRA), D. Hullinger (GSFC/UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean, D. Palmer (LANL),
A. Parsons (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), G. Tagliaferri (OAB)
on behalf of the Swift BAT team:

At 14:06:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB041223.  The spacecraft did not autonomously slew
to the burst since automated slewing was not yet enabled.

The BAT ground-calculated location is RA,Dec 100.183,-37.066 (J2000)
with an uncertainty of 7 arcmin (radius, 3-sigma, including systematic
uncertainty using a preliminary bore-sight alignment calibration).
This is 27 degrees off the BAT bore sight and was in the partially encoded
field of view.

The burst lightcurve is multi-peaked with structure within the peaks
with the main emission lasting ~60 sec.  The peak flux was 7.5 events/cm^2/sec
(1-sec sampling; unsaturated; ~15 to 100 keV; ~28 Crab).
The total duration was ~130 sec.  The fluence was ~2e-5erg/cm^2.
A reduced energy band is being quoted because of our response uncertainty
in the >100 keV band, and because of strong emission by this burst 
in this band.
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