TITLE: GCN CIRCULAR NUMBER: 17999 SUBJECT: Swift Trigger 648422: Swift-XRT observations DATE: 15/07/09 23:25:21 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri, P. D'Avanzo, M.G. Bernardini (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: The XRT began observing the field of the possible transient source near NGC4552 (trigger=648422; Melandri et al., GCN 17998) at 22:38:45.6 UT, 3388.4 seconds after the BAT trigger. No source was detected in 1590 s of promptly downlinked data. Due to the non-detection of a counterpart in the XRT observation, we cannot confirm that this is a real astrophysical source at this time. We await the full downlinked dataset to make a more definitive statement on the nature of this trigger.