TITLE: GCN CIRCULAR NUMBER: 12109 SUBJECT: Swift trigger 456780 is not a burst DATE: 11/07/07 08:08:14 GMT FROM: Wayne Baumgartner at GSFC W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), V. D'Elia (ASDC), P. A. Evans (U Leicester), C. Gronwall (PSU), C. Guidorzi (U Ferrara), E. A. Hoversten (PSU), O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA), K. L. Page (U Leicester), J. L. Racusin (NASA/GSFC), P. Romano (INAF-IASFPA) and B. Sbarufatti (INAF-OAB/IASFPA) report on behalf of the Swift Team: At 07:48:43 UT, the Swift Burst Alert Telescope (BAT) triggered on trigger=456780. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 22.861, +16.758 which is RA(J2000) = 01h 31m 27s Dec(J2000) = +16d 45' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a rapidly rising background as the spacecraft entered the SAA. In addition to the fact that the image significance was less than the 7 sigma canonical threshold, this trigger is not a burst. The XRT began observing the field at 07:49:44.2 UT, 60.9 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. No prompt UVOT data products were received. We are waiting for the full dataset to search for a UVOT counterpart. Burst Advocate for this burst is W. H. Baumgartner (wayne AT milkyway.gsfc.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/too.html.)