TITLE: GCN CIRCULAR NUMBER: 15690 SUBJECT: GRB 140102A: Swift/UVOT Detection DATE: 14/01/06 03:33:36 GMT FROM: Mike Siegel at PSU/Swift MOC L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140102A 65 s after the BAT trigger (Hagen et al., GCN Circ. 15653). We detect a fading source consistent with the XRT position (Goad et al. GCN Circ. 15657) that is detected in all but the bluest UVOT filters. The preliminary UVOT position is: RA (J2000) = 14:07:40.65 = 211.91939 (deg.) Dec (J2000) = +01:19:59.8 = 1.33329 (deg.) with an estimated uncertainty of 0.50 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) 65 215 147 16.07 +/- 0.03 white 557 2215 322 18.38 +/- 0.05 white 6222 7858 393 20.08 +/- 0.21 v 607 2265 194 18.21 +/- 0.23 b 533 2191 175 18.50 +/- 0.15 u (fc) 278 527 245 16.90 +/- 0.05 u 681 2166 155 17.97 +/- 0.14 w1 657 2142 175 19.10 +/- 0.33 m2 631 2117 175 >19.34 w2 6428 8034 364 >19.96 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).