TITLE: GCN CIRCULAR NUMBER: 17964 SUBJECT: GRB 150626A: Swift/UVOT Upper Limits DATE: 15/06/26 13:57:17 GMT FROM: Massimiliano de Pasquale at IASF-Palermo M. De Pasquale (UCL-MSSL) and T. Roegiers (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150626A 98 s after the BAT trigger (Roegiers et al., GCN Circ. 17960). No optical afterglow consistent with the XRT position (Evans GCN Circ. 17961) 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) exposures and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 98 248 147 >20.4 u_FC 311 561 246 >19.6 white 98 1540 392 >21.1 u 311 1490 324 >19.8 v 641 1590 95 >18.8 b 566 1514 97 >19.7 uw1 690 1465 78 >18.8 um2 665 1440 97 >18.6 uw2 616 1390 97 >19.0 The magnitudes in the table are not corrected for the substantial Galactic extinction due to the reddening of E(B-V) = 0.37 in the direction of the burst (Schlegel et al. 1998).