51 TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2853SUBJECT: GRB041217: The First GRB Located On-Board SwiftDATE: 04/12/17 23:59:44 GMTFROM: Ed Fenimore at LANLD. Palmer (LANL), E. Fenimore (LANL), S. Barthelmy (GSFC), G. Chincarini(OAB), J. Cummings (GSFC), N. Gehrels (GSFC), P. Giommi (ASDC), M. Goad(UL), D. Hullinger (UMD), H. Krimm (USRA), C. Markwardt (UMD), K. Mason(MSSL), K. McLean (LANL), J. Nousek (PSU), J. Osborne (UL), A. Parsons(GSFC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), A. Wells(UL), N. White (GSFC), on behalf of the Swift BAT team.On Dec , 7:28:30 UT, the Swift Burst Alert Telescope (BAT)triggered and located on-board an apparent gamma-ray burst. Thespacecraft did not autonomously slew to the burst since automated slewingis not yet enabled.The location is RA/Dec , This is about 42 degrees off thebore sight in the partially encoded field of view. The Swift attitudecontrol system is still undergoing calibration, but we estimate that theposition is within 12 arcmin. The on-orbit location differed from alocation processed on the ground by about 6 arcmin. Aftercalibration we expect on-board locations to be within 4 arcmin.The burst can be characterized as a smooth profile with a rise time of2 sec and a fall time of 6 sec. The T90 was ~6.7. Although BAT is stillundergoing calibration, ground processing gives a power law spectrum witha number index of -1.6 and a fluence of 5E-6 erg/cm2 in the ~20 to 200keV range. The peak was about 4.4 cts/cm2/sec in ~15 to 200 keV.