TITLE: GCN CIRCULAR NUMBER: 19871 SUBJECT: GRB 160826A: Swift/UVOT Upper Limits DATE: 16/08/26 19:00:50 GMT FROM: Mike Siegel at PSU/Swift MOC S. J. LaPorte (PSU) and B. Mingo (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160826A 109 s after the BAT trigger (Mingo et al., GCN Circ. 19866). No optical afterglow consistent with the XRT position (Mingo et al. GCN Circ. 19868) 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 109 259 147 >21.1 u_FC 267 517 246 >19.8 white 109 1195 353 >22.1 v 597 1245 78 >19.8 b 523 1170 58 >20.2 u 267 4893 340 >19.8 w1 648 1290 74 >19.0 m2 622 1269 78 >19.3 w2 573 1220 78 >19.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.47 in the direction of the burst (Schlegel et al. 1998).