TITLE: GCN CIRCULAR NUMBER: 26128 SUBJECT: GRB 191031D: Swift/UVOT Upper Limits DATE: 19/11/01 17:00:34 GMT FROM: Sam LaPorte at PSU GRB 191031D: Swift/UVOT Upper Limits J. D. Gropp (PSU) and V. D'Elia (SSDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 191031D 93 s after the BAT trigger (D'Elia et al., GCN Circ. 26112). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 26117) 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 93 242 147 >20.8 u_FC 306 555 246 >20.2 white 93 6694 575 >21.1 v 636 5863 294 >19.9 b 561 6683 471 >20.4 u 306 6477 697 >20.3 w1 686 6273 452 >19.8 m2 661 6067 294 >19.6 w2 612 5658 294 >19.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.08 in the direction of the burst (Schlegel et al. 1998).