TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4092 SUBJECT: Swift trigger 159578 is not a burst DATE: 05/10/13 21:25:11 GMT FROM: Hans Krimm at NASA-GSFC J. Cummings (GSFC-NRC), A. Beardmore (U. Leicester), D. Burrows (PSU), N. Gehrels (GSFC), O. Godet (U. Leicester), C. Gronwall (PSU), J. Kennea (PSU), H. Krimm (GSFC-USRA), F. Marshall (GSFC), K. Page (U. Leicester), D. Palmer (LANL), on behalf of the Swift team: Analysis of the Swift-BAT event data, the Swift-XRT Image Mode frame and the first two orbits of XRT PC mode data (1.2 ksec) for trigger 159578 (Cummings et al., GCN 4091) reveals no point source. Therefore we conclude that it is not due to a GRB or other astrophysical source. This trigger was likely due to the chance coincidence of a rate increase as the satellite was entering the SAA and a positive fluctuation in the image domain.