////////////////////////////////////////////////////////////////////////
TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2918
SUBJECT: GRB041228: Swift-BAT detection of a burst
DATE:    04/12/28 18:08:18 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott@lheamail.gsfc.nasa.gov>

A. Parsons, S. Barthelmy, L. Barbier (GSFC), S. Campana (OAB),
J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC),
J. Hill (PSU), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), F. Marshall (GSFC), K. McLean (LANL),
D. Palmer (LANL), T. Sakamoto (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), 
M. Tashiro (Saitama), J. Tueller (GSFC)
on behalf of the Swift-BAT team:

At 10:49:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on-board GRB041228.  The spacecraft did not autonomously slew
to the burst since automated slewing was not yet enabled.

The BAT ground-calculated location is RA,Dec 336.641,+5.050 (J2000)
with an uncertainty of 5 arcmin (radius, 3-sigma, including a systematic
uncertainty).  The lightcurve is multi-peaked with a main emission duration
of ~40 s, with 36 counts/cm^2 fluence and a peak (1 second interval)
of ~1.2 counts/cm^2/s in the 15-350 keV band.  And there appears to be
extended emission for another 80 sec.

////////////////////////////////////////////////////////////////////////
TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2919
SUBJECT: GRB041228: ROTSE-III Optical Observations
DATE:    04/12/28 20:03:23 GMT
FROM:    Eli Rykoff at U of Michigan/ROTSE  <erykoff@umich.edu>

E. Rykoff (U. Michigan) reports on behalf of the ROTSE collaboration:

ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, 
responded to Swift GRB041228 (GCN #2918).  An automatic response was 
initiated during early twilight hours.  The first usable image was taken 
at 28 Dec 18:38:44 UT, 7.8 hours after the burst.  We took 50 60-s 
exposures before the burst position dropped below our minimum observing 
elevation.  The unfiltered images were calibrated relative to USNO A2.0. 
  Individual images have limiting magnitudes ranging from 17-18 as the 
sky darkened.    Comparison to DSS (second epoch) reveals no new sources 
within the 3-sigma error circle to a limiting magnitude of 18.8 for 
stacks of 10 images taken 8.4 hours after the burst.