TITLE: GCN CIRCULAR NUMBER: 24815 SUBJECT: GRB 190613A: Swift/UVOT Detection DATE: 19/06/13 17:36:46 GMT FROM: Frank Marshall at Swift/UVOT F. E. Marshall (NASA/GSFC) and E. Ambrosi (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 190613A 145 s after the BAT trigger (Ambrosi et al., GCN Circ. 24798). A source consistent with the enhanced XRT position (Osborne et al. GCN Circ. 24809) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 12:10:07.01 = 182.52920 (deg.) Dec (J2000) = +67:14:07.0 = 67.23529 (deg.) with an estimated uncertainty of 0.43 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 145 295 147 17.88 +/- 0.04 v 634 1061 58 18.63 +/- 0.29 b 560 753 39 18.93 +/- 0.21 u 303 553 246 18.88 +/- 0.11 w1 685 11118 1121 >20.1 m2 5323 6859 296 >20.8 w2 4913 6548 393 >21.5 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).