TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4211 SUBJECT: GRB 051109: ROTSE-III Detection of Possible Counterpart DATE: 05/11/09 01:21:11 GMT FROM: Eli Rykoff at U of Michigan/ROTSE E.S. Rykoff (U Mich), B. Schaefer (Louisiana State), W. Rujopakarn (U Mich), F. Yuan (U Mich), R. Quimby (U Texas), report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 051109 (Swift trigger 163136). The first image was at 01:12:52.7 UT, 32.1 s after the burst (4.7 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a new object, not visible in the DSS (second epoch), with coordinates: 22:01:15.3 +40:49:23.3 (J2000) start UT mag mlim(of image) ---------------------------------- 01:12:52.7 15.4 16.8 Continuing observations are in progress.