TITLE: GCN CIRCULAR NUMBER: 13418 SUBJECT: GRB 120703A: Swift/UVOT Detection DATE: 12/07/05 14:00:15 GMT FROM: Craig Swenson at PSU/Swift C. A. Swenson (PSU) and B.-B. Zhang (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120703A 90 s after the BAT trigger (Zhang et al., GCN Circ. 13408). A source consistent with the XRT position (Goad et al., GCN Circ. 13415) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 22:37:25.67 = 339.35694 (deg.) Dec (J2000) = -29:43:23.8 = -29.72327 (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 90 240 147 18.48 ± 0.06 v 4299 4499 197 >19.5 b 3684 5249 325 >20.9 u 304 416 110 18.07 ± 0.13 w1 4710 4909 197 >19.5 m2 4504 4704 197 >21.4 w2 4095 4294 197 >21.4 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).