TITLE: GCN CIRCULAR NUMBER: 11412 SUBJECT: GRB 101117B: Swift/UVOT Discovery of an Optical Afterglow DATE: 10/11/17 19:42:13 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC Stephen Holland (CRESST/USRA/GSFC) reports, on behalf of the UVOT Team The Swift/UVOT source list has an uncatalogued source at the location of the XRT afterglow (Wolf et al. 2010, GCNC 1141). Preliminary photometry indicates an approximate white magnitude of 18.2.