Gamma-ray Burst 041228

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #2918
  

  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  
  

  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.
• GCN notice #2919
  

  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  
  

  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.