TITLE: GCN CIRCULAR NUMBER: 31057 SUBJECT: GRB 211107B: Swift/BAT detection DATE: 21/11/08 22:11:57 GMT FROM: Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com> Swift/BAT did not successfully trigger on GRB 211107B (T0: 2021-11-07 17:27:10 UTC). Swift/BAT triggered in real-time onboard in the rates domain (trigger #1082818), but no strong source was found to be associated in the onboard imaging. This 'failed trigger' resulted in 10s of BAT TTE data being saved and sent to the ground. The duration of the burst, as seen by BAT, is ~15 seconds. In ground analysis of the available TTE data, we find the position of the burst with SNR 12.6 in the image domain. The BAT position is RA, Dec = 65.7949 -27.5524, which is: RA (J2000) 04h 23m 10.78s Dec (J2000) -27d 33' 8.6" with an estimated uncertainty of 2 arcminutes. XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars.