TITLE: GCN CIRCULAR NUMBER: 15086 SUBJECT: GRB130807A: Swift/UVOT observations DATE: 13/08/08 19:53:04 GMT FROM: Massimiliano de Pasquale at MSSL-UCL M. De Pasquale (UCL-MSSL) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130807A 145 s after the BAT trigger (Melandri et al., GCN Circ. 15082). No optical source consistent with the XRT position (Melandri et al., GCN Circ. 15085) is detected in the 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 summed exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 3572 3722 147 >20.3 white 3572 5573 541 >21.1 v 4348 5984 393 >19.3 b 3732 5369 393 >20.3 u_FC 145 311 163 >19.7 u 145 5164 360 >19.9 w1 4759 4959 197 >19.6 m2 4552 6078 284 >19.7 w2 4143 5780 393 >20.2 The magnitudes in the table are not corrected for the strong Galactic extinction corresponing to the reddening of E(B-V) = 2.03 in the direction of the burst (Schlegel et al. 1998).