TITLE: GCN CIRCULAR NUMBER: 16088 SUBJECT: GRB 140408A: Swift/UVOT Upper Limits DATE: 14/04/09 07:42:56 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (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 140408A 109 s after the BAT trigger (D'Elia et al., GCN Circ. 16082). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 16085,) and with the non-detection reported by Kuroda et al. (GCN Circ. 16086), 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 >20.9 u_FC 321 571 246 >20.5 white 109 1025 334 >21.2 v 652 4403 236 >20.0 b 577 769 39 >18.7 u 321 745 265 >20.5 w1 701 720 19 >18.1 m2 676 4572 201 >19.9 w2 627 1046 54 >20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.19 in the direction of the burst (Schlegel et al. 1998).