TITLE: GCN CIRCULAR NUMBER: 17424 SUBJECT: GRB 150206A: Swift/UVOT Detection DATE: 15/02/07 10:26:33 GMT FROM: Samantha Oates at MSSL S. R. Oates (IAA-CSIC/UCL-MSSL) and L. M. Z. Hagen (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150206A 483 s after the BAT trigger (Hagen et al., GCN Circ. 17413). A source consistent with the XRT position (Goad et al. GCN Circ. 17418) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 00:40:17.63 = 10.07346 (deg.) Dec (J2000) = -63:10:55.7 = -63.18214 (deg.) with an estimated uncertainty of 0.52 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 483 577 93 18.76 +/- 0.17 v 2091 6690 201 >18.8 b 2190 2912 255 19.56 +/- 0.22 u 2165 2707 78 >19.0 w1 2140 2683 78 >18.9 w2 2414 6560 216 >19.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).