TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4775 SUBJECT: GRB 060218: Swift-BAT detection of a possible burst DATE: 06/02/18 04:28:55 GMT FROM: Scott Barthelmy at NASA/GSFC G. Cusumano (IASF-Pa INAF), S. Barthelmy (GSFC), N. Gehrels (GSFC), S. Hunsberger (PSU), S. Immler (GSFC), F. Marshall (GSFC), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU) on behalf of the Swift team: At 03:34:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060218 (trigger=191157). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 50.404, +16.866 deg {03h 21m 37s, +16d 51' 58"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The TDRSS lightcurve shows nothing, which is consistent and common for an image trigger. The XRT began taking data at 03:37:04 UT, 153 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image and no prompt position is available. We are waiting for down-linked data to detect and determine a position for the source. The UVOT began taking data 152 seconds after the BAT trigger. There is an indication of an afterglow candidate at RA,Dec 03h 21m 39.8s,+16d 52' 06" +/- 1 arcsec with an estimated B magnitude of 19.4.