TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2721 SUBJECT: XRF040916: optical follow-up observations DATE: 04/09/17 18:51:51 GMT FROM: Kuiyun Huang at IANCU XRF040916: optical follow-up observations W.L. Wu, K.Y. Huang, W.H. Ip (NCU) Y. Urata, T. Tamagawa (RIKEN) report : "We have observed the optical candidate reported by Kilmaritin et al. (GCN 2715) with 1.0m telescope at Lulin Observatory (National Central University, Taiwan). We obtain I-band images with 600 sec exposure on 2004 16 Sep. 16.68 UT (16.3 hr after burst) and 17 Sep. 12.51 UT (1.5 day after burst). We can not find any variablity for the source. The brithness of the source are OT candidate seeing 16 Sep. 16.68 UT I = 19.6 2.0 arcsec 17 Sep. 12.51 UT I = 19.7 2.5 arcsec The limiting magnitude is around 20.1 which comparison with USNO A.2 red magnitude." This message may be cited