TITLE: GCN CIRCULAR NUMBER: 18716 SUBJECT: Trigger 668097: Swift detection of V 404 Cyg DATE: 15/12/23 05:35:49 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 05:19:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located V 404 Cyg (trigger=668097). Swift did not slew due to a low merit value. The BAT on-board calculated location is RA, Dec 306.024, +33.874, which is RA(J2000) = 20h 24m 06s Dec(J2000) = +33d 52' 27" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical with image triggers, the real-time light curve does not show anything. This is a known source, and as such the assigned merit value was low enough to not allow an immediate slew. Swift will slew to this source at 06:37 UT.