TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4411 SUBJECT: GRB 051227: Swift/UVOT Upper Limits (Possible U-band DATE: 05/12/28 19:40:53 GMT FROM: Pete Roming at PSU P. Roming (PSU), L. Barbier (GSFC), M. Trippico (GSFC-SSAI), J. Nousek (PSU) on behalf of the Swift/UVOT team We have created summed images from Swift UVOT exposures of GRB051227 (Barbier et al., GCN 4397) taken through each of the broadband filters. No source was detected at the XRT position (Beardmore et al. GCN 4402) or the R-band VLT position (Malesani, GCN 4404) down to the following 5-sigma upper limits (no correction has been made for the expected visual extinction of about 0.14 magnitudes): Filter T_range(s) Tot Exp(s) 5sigUL(mag) V 96-4092 496 19.0 B 462-10250 617 20.2 U 408-6370 502 19.6 UVW1 354-5904 950 19.6 UVM2 300-4996 950 19.7 UVW2 571-3988 113 18.5 White 516-565 100 19.2 We note that from the U-band summed image a source is detected by the Swift analysis tool, uvotsource, at the 4.0-sigma confidence coincident with the position reported by Malesani. The magnitude is 19.8+/-0.3.