TITLE: GCN CIRCULAR NUMBER: 23407 SUBJECT: GRB 181103A: Swift/UVOT Detection DATE: 18/11/04 14:47:19 GMT FROM: Sam LaPorte at PSU GRB 181103A: Swift/UVOT Detection S. J. LaPorte (PSU) and A. Tohuvavohu (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 181103A 92 s after the BAT trigger (Tohuvavohu et al., GCN Circ. 23402). A fading source is detected in the initial UVOT exposures at a position consistent with the XRT position (Evans et al., GCN Circ. 23403). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag b 534 898 58 >19.08 uvm2 632 1126 57 >18.19 u 279 874 530 19.58+-0.25 v 608 1103 58 >18.21 uvw1 657 849 38 >18.16 uvw2 584 1079 58 >18.36 white_FC 121 271 294 20.47+-0.29 white 559 6763 579 >21.12 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).