TITLE: GCN CIRCULAR NUMBER: 26398 SUBJECT: GRB 191213A: Swift detection of a burst DATE: 19/12/13 04:16:19 GMT FROM: David Palmer at LANL S. B. Cenko (GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), J.D. Gropp (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 04:06:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191213A (trigger=944091). Due to a Sun constraint, Swift did not slew to this burst. The BAT on-board calculated location is RA, Dec 224.507, -9.726 which is RA(J2000) = 14h 58m 02s Dec(J2000) = -09d 43' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, there is no obvious variation in the immediately-available lightcurve. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 16:25 UT on 2019 December 23. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). 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/)