TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4219 SUBJECT: GRB 051109: Rc and Ic observations DATE: 05/11/09 06:14:38 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) reports: The error region of GRB 051109 (Tagliaferri et al. GCN 4213) was observed by the 0.3 m telescopes in the New Mexico Skies Observatory. Starting at 01:17:46 UT (326 s after the burst), 120 s exposures in Ic band was obtained. We also observed the field in Rc band (120 s exposures) with another 0.3 m telescope at the same site, starting at 01:29:39 UT. As a result of the preliminary analysis, the optical afterglow (Rykoff et al. GCN 4211) is detected in Ic band as follows, relative to USNO-B1.0 I magnitude. ------------------------------------------ StartUT Filter Mag Nframes ------------------------------------------ 01:25:25 Ic 16.6 1 ------------------------------------------