TITLE: GCN CIRCULAR NUMBER: 4428 SUBJECT: Swift-BAT trigger 175653 is not an astrophysical source DATE: 06/01/03 21:23:27 GMT FROM: Scott Barthelmy at NASA/GSFC D. Grupe (PSU), S. Barthelmy (GSFC), T. Sakamoto (GSFC/NRC), M. Chester (PSU), F. Marshall (GSFC), N. Gehrels (GSFC), D. Burrows (PSU), J. Kennea (PSU), A. Retter (PSU) on behalf of the Swift team: We have analyzed the full BAT data set. Trigger 175653 (Grupe et al. 2006, GCN 4426) is due to (a) a chance fluctuation in the rate domain, (b) superposed on a rising background while entering the SAA, or (c) a chance fluctuation in the image domain. The spacecraft slewed immediately to the BAT position, but because the spacecraft was in the SAA, XRT only took a 2s image which did not show any bright source. XRT started observing again on 2006-January-03 05:19 UT about 75 minutes after the trigger. This data set has a total observing time of 3.6 ks. We do not find any source within the 3 arcmin BAT error circle. No afterglow candidate was identified by UVOT's automated processing either. Therefore we consider this trigger as false and not due to a GRB or any astrophysical source.