TITLE: GCN CIRCULAR NUMBER: 3196 SUBJECT: GRB 050408: Optical afterglow confirmed DATE: 05/04/08 22:50:57 GMT FROM: Kuiyun Huang at IANCU GRB 050408: Optical afterglow confirmed K.Y. Huang, W.H. Ip, D. Kinoshita (NCU), Y. Urata, T. Tamagawa (RIKEN), Y. Qiu (BAO) and Y.Q. Lou (THCA) on behalf of the East-Asia GRB Follow-up Observation Network (EAFON)report: " We have started the observation for the field of GRB 050408 at 17:10 UT on Apr 08 (55 min after the burst). Using Lulin-One meter Telescope (LOT), we have performed 'VR broad band' filter imaging observation. These images show a source in the Swift/XRT error circle. The coordinate is consistent with that of A. de Ugarte Postigo et al. (GCN 3193). Based on our preliminary 'VR-band' photometry, the source shows variability which decay index is about -0.6 between 17:17(UT) and 18:33(UT). This source is therefore likely to be the optical afterglow of GRB 050408. Further analysis is in progress. This message may be cited."