TITLE: GCN CIRCULAR NUMBER: 18970 SUBJECT: GRB 160131A Swift/UVOT Detection DATE: 16/02/01 18:09:05 GMT FROM: Marissa McCaule at PSU L. M. McCauley (PSU), K. L. Page (U Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160131A 78 s after the BAT trigger (Page et al., GCN Circ. 18951). A fading source consistent with the XRT position (Beardmore et al. GCN Circ. 18159) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 05:12:40.33 = 78.16804 (deg.) Dec (J2000) = -07:02:58.81 = -7.04967 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits 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 78 228 147 13.77+-1.10 white 5051 11361 1081 16.71+-0.02 v 4026 5662 393 15.72+-0.03 b 4846 10449 1138 16.81+-0.02 u 290 540 245 13.08+-0.03 u 4641 6277 393 15.64+-0.03 uvw1 4436 6072 393 16.18+-0.04 uvm2 4231 5867 393 16.64+-0.06 uvw2 3821 12083 1098 17.43+-0.05 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.11 in the direction of the burst (Schlegel et al. 1998).