TITLE: GCN CIRCULAR NUMBER: 21079 SUBJECT: Swift Trigger 752193 is not a GRB DATE: 17/05/10 06:36:18 GMT FROM: Kim Page at U.of Leicester A. D'Ai (INAF-IASFPA), V. D'Elia (ASDC), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 06:12:15 UT, the Swift Burst Alert Telescope (BAT) triggered on increasing count rate due to the approach to the SAA and produced an image with a marginal-significance peak (trigger=752193). The BAT light curve shows the increasing count rate due to approaching the SAA, but no obvious peak at the trigger time. The XRT began observing the field at 06:13:06.4 UT, 51.1 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. Due to the lack of a clear peak in the BAT lightcurve, the marginal (6.5 sigma) BAT image peak, and the lack of an XRT counterpart, we believe that this event was due to particle background near the SAA and is not an astrophysical event.