TITLE: GCN CIRCULAR NUMBER: 7150 SUBJECT: GRB071227: Swift/UVOT refined analysis DATE: 07/12/28 04:00:24 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara (PSU), T. Sakamoto (GSFC/UMBC) report on behalf of the Swift-UVOT team: The Swift/UVOT observed the field of GRB071227 (trigger #299787) starting 86 seconds after the BAT trigger (Sakamoto et al.2007, GCN Circ. 7147). We do not find any new source in any of the UVOT single observations inside the XRT error circle. Coadding all the images for each single filter an OT candidate has been detected at 3-sigma confidence level in the White filter coadded image at the position RA: 03:52:31.102 DEC: -55:59:00.65 with an uncertainty of 0.6 arcsec (90% confidence). This position is 4.5 arcsec from the XRT position. The 3-sigma upper limits and the detection(in the UVOT photometric system,Breeveld et al., GCN Circ. 6614) are listed. Filter Tstart Tstop Exp Magnitude (s) (s) (s) White 86 6129 609 21.73 +- 0.36 v 68 6539 828 > 20.46 b 673 5923 409 > 21.01 u 648 5718 230 > 20.33 uvw1 624 5512 239 > 20.17 uvm2 599 10886 1191 > 21.00 uvw2 703 6334 419 > 20.65 The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.01 mag in the direction of the burst (Schlegel et al. 1998).