TITLE: GCN CIRCULAR NUMBER: 18322 SUBJECT: GRB 150915A: Swift UVOT upper limits DATE: 15/09/16 17:53:39 GMT FROM: Scott Barthelmy at NASA/GSFC A. A. Breeveld (UCL-MSSL) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150915A 295s after the BAT trigger (D'Elia et al., GCN Circ. 18315). No optical afterglow consistent with the XRT position (D’Elia et al., GGN Circ. 18315) or the GROND position (Yates et al., GCN Circ. 18317) 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 u_FC 295 545 246 >20.0 white 576 769 39 >19.9 v 625 818 39 >18.2 b 550 745 39 >19.2 u 295 4267 434 >20.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).