TITLE: GCN CIRCULAR NUMBER: 5918 SUBJECT: GRB 061214(?): Swift detection of a possible burst DATE: 06/12/14 12:39:01 GMT FROM: Scott Barthelmy at NASA/GSFC S. B. Pandey (UCL-MSSL), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), M. M. Chester (PSU), P. A. Evans (U Leicester), O. Godet (U Leicester), C. Guidorzi (Univ Bicocca&INAF-OAB), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), T. Mineo (INAF-IASFPA), S. R. Oates (UCL-MSSL), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC), P. Romano (Univ. Bicocca & INAF-OAB), P. Schady (MSSL-UCL), R. L. C. Starling (U Leicester) and E. Troja (INAF-IASFPA) report on behalf of the Swift Team: At 12:16:53 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 061214 (trigger=250908). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 7.777, -29.640 which is RA(J2000) = 00h 31m 06s Dec(J2000) = -29d 38' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Given that this is a 4-msec trigger in the high energy band makes this likely that this trigger is a cosmic ray shower. The BAT light curve shows nothing significant, which is also consistant with a cosmic ray shower. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. Prior to receiving the full data set in the next downlink, it seems equally likely at this point that this is cosmic ray shower or a GRB. The XRT began taking data at 12:18:15 UT, 82 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. Analysis of promptly downlinked photon counting data reveals no source in a 163 s exposure. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 87 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The 3-sigma upper limit is 19.9 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02.