{
  "bibcode": "2004GCN..2853....1P",
  "body": "D. Palmer (LANL), E. Fenimore (LANL), S. Barthelmy (GSFC), G. Chincarini\n(OAB), J. Cummings (GSFC), N. Gehrels (GSFC), P. Giommi (ASDC), M. Goad\n(U.Leicester), D. Hullinger (UMD), H. Krimm (USRA), C. Markwardt (UMD), K. Mason\n(MSSL), K. McLean (LANL), J. Nousek (PSU), J. Osborne (U.Leicester), A. Parsons\n(GSFC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), A. Wells\n(U.Leicester), N. White (GSFC), on behalf of the Swift BAT team.\n\nOn Dec 17 2004, 7:28:30 UT, the Swift Burst Alert Telescope (BAT)  \ntriggered and located on-board an apparent gamma-ray burst. The\nspacecraft did not autonomously slew to the burst since automated slewing\nis not yet enabled.\n\nThe location is RA/Dec 164.79, -17.95 (J2000). This is about 42 degrees off the\nbore sight in the partially encoded field of view. The Swift attitude\ncontrol system is still undergoing calibration, but we estimate that the\nposition is within 12 arcmin (radius). The on-orbit location differed from a\nlocation processed on the ground by about 6 arcmin. After \ncalibration we expect on-board locations to be within 4 arcmin.\n\nThe burst can be characterized as a smooth profile with a rise time of\n2 sec and a fall time of 6 sec. The T90 was ~6.7. Although BAT is still\nundergoing calibration, ground processing gives a power law spectrum with\na number index of -1.6 and a fluence of 5E-6 erg/cm^2 in the ~20 to 200\nkeV range. The peak was about 4.4 cts/cm^2/sec in ~15 to 200 keV.\n\n[GCN OPS NOTE (18-19dec04): \"UL\" was changed to \"U.Leicester\".  And the words\n\"(J2000)\" and \"(radius)\" were added to the position estimate.]",
  "circularId": 2853,
  "createdOn": 1103327984000,
  "email": "efenimore@lanl.gov",
  "subject": "GRB041217: The First GRB Located On-Board Swift",
  "submitter": "Ed Fenimore at LANL  <efenimore@lanl.gov>",
  "eventId": "GRB 041217"
}