TITLE: GCN CIRCULAR NUMBER: 15795 SUBJECT: GRB 140206A: Swift/UVOT Detection DATE: 14/02/06 18:20:25 GMT FROM: Samantha Oates at MSSL S. R. Oates (UCL-MSSL) and A. Y. Lien (NASA/GSFC/ORAU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140206A 52 s after the BAT trigger (Lien et al., GCN Circ. 15784). A source consistent with the XRT position (Osborne et al. GCN Circ. 15793) and the optical positions reported by Oksanen et al. (GCN 15786) and Yurkov et al. (GCN 15788) is detected in the initial UVOT exposures. The lack of detections in the UV filters suggests a redshift ~2 - 3. The preliminary UVOT position is: RA (J2000) = 09:41:20.26 = 145.33442 (deg.) Dec (J2000) = +66:45:38.6 = 66.76072 (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 52 202 147 15.88 +/- 0.02 v 596 616 20 15.75 +/- 0.11 b 522 542 20 16.51 +/- 0.09 u 264 514 246 16.18 +/- 0.04 w1 645 17944 963 >20.9 m2 16137 24450 1607 >21.2 w2 21898 22798 886 >21.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.14 in the direction of the burst (Schlegel et al. 1998).