TITLE: GCN CIRCULAR NUMBER: 10766 SUBJECT: GRB 100514A: Swift/UVOT Observations DATE: 10/05/15 16:12:01 GMT FROM: Frank Marshall at GSFC F.E. Marshall (NASA/GSFC) and C.B. Markwardt (CRESST/GSFC/UMD) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 100514A 110 s after the BAT trigger (Markwardt et al., GCN Circ. 10759). There is a marginal (2.6-sigma) detection of a possible optical afterglow at the enhanced XRT position (M.R. Goad et al., GCN Circ. 10762) in the first white finding chart. There is no detection in any of the other initial UVOT exposures. Preliminary results (3-sigma upper limits or values with 1-sigma uncertainties) using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the finding chart (FC) exposures and summed subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 110 260 147 21.1 +/- 0.3 u_FC 268 518 246 >20.2 white 549 7708 516 >21.0 v 600 6843 529 >20.0 b 524 7666 529 >20.5 u 268 7459 775 >20.5 w1 650 7254 529 >21.0 m2 624 7048 529 >20.2 w2 574 6639 352 >19.9 The values quoted above 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).