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GCN Circular 2886

GRB041219c: Third Burst in One Day from Swift-BAT
2004-12-20T18:22:19Z (20 years ago)
Craig Markwardt at GSFC <>
C. Markwardt (UMD), L. Barbier, S. Barthelmy (GSFC), 
P. Boyd (UMBC), S. Campana (OAB), J. Cummings (GSFC), 
E. Fenimore (LANL), M. Galassi (LANL), N. Gehrels (GSFC), 
M. Goad (U.Leicester), D. Hullinger (UMD), H. Krimm (USRA), 
K. McLean (LANL), J. Norris (GSFC), D. Palmer (LANL),
A. Parsons (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), 
T. Takahashi (ISAS), J. Tueller (GSFC) 
on behalf of the Swift BAT team.

At 20:30:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB041219c (BAT Trigger #100380).  This is the third
burst detected and imaged by BAT on Dec 19.  The spacecraft did not
autonomously slew to the burst since automated slewing is not yet
enabled.  Automated notification through TDRSS is also disabled during
this early commissioning phase of the mission.

The ground-calculated location is RA, Decl. 343.966, -76.802 (J2000)
with an uncertainty of 12 arcmin (radius, including a large systematic
uncertainty due to the lack of an on-orbit bore-sight alignment
calibration).  This is ~43 degrees off the BAT bore sight and is ~50%
encoded.  It was imaged at >19 sigma.  The source is 39 degrees from
the galactic plane.

The burst contained at least two peaks, each peak with a full-width,
half-maximum of ~7 seconds, for a total duration of ~40 seconds.
There is a possible faint precursor 40 seconds earlier which may or
may not be from GRB 041219c (it cannot be determined with the data at
hand).  The peak flux was 1.5 events/cm^2/sec in the 15-350 keV band
(~6 Crab).  

The spectrum appears to be soft based on the light curve.
The total fluence is approximately 21 events/cm^2 (15-350 keV), or
2E-6 erg/cm^2.
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