TITLE: GCN CIRCULAR NUMBER: 12107 SUBJECT: Swift Trigger 456659 is probably not astrophysical DATE: 11/07/05 10:05:01 GMT FROM: David Palmer at LANL V. Mangano (INAF-IASFPA), W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB), M. M. Chester (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), O. M. Littlejohns (U Leicester), C. B. Markwardt (NASA/GSFC), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 09:21:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger 456659. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 45.476, +2.977 which is RA(J2000) = 03h 01m 54s Dec(J2000) = +02d 58' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). At present we do not have data to characterize this trigger. We believe that the trigger occurred on the rising edge of the South Atlantic Anomaly. Also, the trigger significance is 6.7 which is less than 7 sigma. Thus, the trigger is likely to be non-astrophysical. The XRT began observing the field at 09:22:32.2 UT, 84.5 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. Due to a telemetry outage, further information will require the Malindi downlinked data in a couple of hours. At that time it will be possible to determine the reality of this event. Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). 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.)