TITLE: GCN CIRCULAR NUMBER: 16924 SUBJECT: GRB 141017A: Swift/UVOT Detection DATE: 14/10/18 11:06:06 GMT FROM: Samantha Oates at MSSL S. R. Oates (IAA-CSIC/UCL-MSSL) and F. E. Marshall (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 141017A 92 s after the BAT trigger (Marshall et al., GCN Circ. 16919). A source consistent with the XRT position (Goad et al. GCN Circ. 16921) is detected in the initial UVOT white filter exposures. 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) 92 242 150 20.54 +/- 0.25 white 859 1009 159 >20.91 v 633 13060 691 >20.0 b 559 17991 1306 >21.4 u 304 7171 717 >20.7 w1 683 6966 471 >20.3 m2 5133 6761 388 >20.1 w2 6152 12850 1082 >21.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).