TITLE: GCN CIRCULAR NUMBER: 29061 SUBJECT: GRB 201216C: Swift detection of a burst DATE: 20/12/16 23:15:47 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), M. J. Moss (GWU), K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 23:07:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 201216C (trigger=1013243). Swift did not slew immediately to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 16.358, +16.537 which is RA(J2000) = 01h 05m 26s Dec(J2000) = +16d 32' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 50 sec. The peak count rate was ~13000 counts/sec (15-350 keV), at ~20 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+46.8 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)