TITLE: GCN CIRCULAR NUMBER: 17959 SUBJECT: Swift Trigger 646423 is GS 1354-645 DATE: 15/06/25 14:37:58 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), P. A. Evans (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. G. R. Roegiers (PSU), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 14:15:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GS 1354-645 (trigger=646423). Swift did not slew due to observing constraint. The BAT on-board calculated location is RA, Dec 209.512, -64.734, which is RA(J2000) = 13h 58m 03s Dec(J2000) = -64d 44' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, there is nothing of note in the real-time light curve. Due to an observing constraint, Swift will not slew until T0+61.8 minutes. There will be no XRT or UVOT data until this time. This source is currently in outburst as described in ATel #7612, #7614, #7620, #7637, #7656 and has been observed by Swift with a ToO campaign.