GCN Circular 24945
GRB 190630C: Swift/UVOT Upper Limits K. K. Simpson (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 190630C 136 s after the BAT trigger (Ukwatta et al., GCN Circ. 24927). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 24930) is detected in the initial UVOT exposures. Preliminary 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 white_FC 157 307 147 >20.5 white 157 307 147 >20.5 v 136 412 32 >18.1 w2 367 387 19 >20.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.11 in the direction of the burst (Schlegel et al. 1998).