TITLE: GCN CIRCULAR NUMBER: 28565 SUBJECT: GRB 201006A: Swift/UVOT Upper Limits DATE: 20/10/06 21:07:13 GMT FROM: Frank Marshall at Swift/UVOT F. E. Marshall (NASA/GSFC) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 201006A 88 s after the BAT trigger (Gropp et al., GCN Circ. 28560). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 28562) 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 88 238 147 >21.1 u_FC 300 549 246 >20.2 white 88 1539 385 >21.0 v 629 1423 97 >18.9 b 555 1521 97 >19.8 u 300 722 265 >20.3 w1 678 1472 97 >18.7 w2 1205 1225 19 >17.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 1.27 in the direction of the burst (Schlegel et al. 1998).