TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5273 SUBJECT: Trigger 215279: Swift detection of a possible burst (GRB 060619) DATE: 06/06/19 12:10:42 GMT FROM: Scott Barthelmy at NASA/GSFC S. T. Holland (GSFC/USRA), S. D. Barthelmy (GSFC), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-OAB) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift Team: At 11:41:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB (trigger=215279). Swift slewed immediately to the location. The BAT on-board calculated location is RA,Dec 33.362, +30.077 {02h 13m 27s, +30d 04' 36"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Since the trigger occurred on the rising edge of the SAA, the background is very high and it is difficult to determine if there is any emission. The XRT began observing the field at 11:43:39 UT, 156 seconds after the BAT trigger. The XRT downlinked image reveals a large number of cosmic ray events in the field due to the SAA. The XRT centroided on one of these cosmic ray events, and therefore the position message sent through GCN is incorrect and should be ignored. There is no evidence for any X-ray source in the field. The UVOT has not begun observations of this field, due to entry into SAA just prior to the BAT trigger. We will be issuing another circular after we get the full data set downlinked. Due to the onset of the Malindi gap in downlink passes, this may take up to 10 hours to get the full data on this trigger.