TITLE: GCN CIRCULAR NUMBER: 11899 SUBJECT: GRB 110407A : Lulin optical afterglow detection DATE: 11/04/07 16:48:39 GMT FROM: Kuiyun Huang at ASIAA GRB 110407A : Lulin optical afterglow detection C.J. Chuang, C.S. Lin, Y. Urata (NCU) and K.Y. Huang (ASIAA) on behalf of the EAFON cooperation: The 1-m telescope at Lulin Observatory started to observe GRB110407A (Wolf et al. GCN 11849) at 21 minutes after the BAT trigger. A series of our r'-band observations found a fading optical source in the XRT error region reported by Evans (GCN 11896). The position of the optical afterglow candidate is RA(J200) = 12:24:07.534 Dec(J200) = +15:42:46.63 with 1" error. We estimated the brightness of the optical transient against with several SDSS stars. Time (sec) mag(AB) error 1438 20.9 0.1 4758 22.7 0.3 This message may be cited