TITLE: GCN CIRCULAR NUMBER: 18945 SUBJECT: GRB 160127A: Swift/UVOT Detection DATE: 16/01/27 20:48:49 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and Amaral-Rogers (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160127A 82 s after the BAT trigger (Amaral-Rogers et al., GCN Circ. 18938). A fading source consistent with the XRT position (Evans et al. GCN Circ. 18940) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 15:03:55.76 = 225.98234 (deg.) Dec (J2000) = +00:04:22.5 = 0.07291 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 82 232 147 17.59 +/- 0.04 white 574 2411 342 18.66 +/- 0.08 white 6837 7037 196 20.85 +/- 0.28 v 624 1942 156 18.46 +/- 0.19 b 550 1174 58 18.58 +/- 0.16 u (fc) 295 545 246 17.25 +/- 0.05 u 698 2362 174 18.31 +/- 0.13 u 6427 19117 1004 20.92 +/- 0.31 w1 674 1124 58 17.87 +/- 0.20 m2 824 1966 117 19.07 +/- 0.32 w2 600 1917 136 19.56 +/- 0.32 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998).