TITLE: GCN CIRCULAR NUMBER: 34234 SUBJECT: GRB 230723B: Swift detection of a burst DATE: 23/07/23 11:54:24 GMT FROM: K.L. Page at U Leicester K. L. Page (U Leicester), J.D. Gropp (PSU), H. A. Krimm (NSF), T. M. Parsotan (GSFC/UMBC/CRESSTII) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 11:42:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230723B (trigger=1180410). The BAT on-board calculated location is RA, Dec 250.379, -5.327 which is RA(J2000) = 16h 41m 31s Dec(J2000) = -05d 19' 37" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 10 sec. The peak count rate was ~2200 counts/sec (15-350 keV), at ~1 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+50.2 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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/)