TITLE: GCN CIRCULAR NUMBER: 5629 SUBJECT: GRB 060927A: ROTSE-III Detection of Optical Counterpart DATE: 06/09/27 15:12:21 GMT FROM: Brad Schaefer at LSU B. E. Schaefer (Louisiana State), S.A. Yost (U Mich), F. Yuan (U Mich), report on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 060927A (Swift trigger 231362). The first image was at 14:07:51.8 UT, 16.5 s after the burst (4.8 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a fading source with coordinates: 21:58:11.93 +05:21:50.32 (J2000) start UT mag ----------------------- 14:07:51.8 16.5 14:08:05.8 17.1 This source faded fast over the next minute and was well seen in only our first three images. This source is not visible in DSS (second epoch), 2MASS, or the MPChecker database. Continuing observations are in progress.