GCN Circular 6497
Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit E. S. Rykoff, F. Yuan, S. A. Yost (U. Mich), report on behalf of the ROTSE collaboration: ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 070611 (Swift trigger 282003; Stroh et al., GCN 6494), producing images beginning 7.6 s after the GCN notice time, as reported in GCN 6495 (Schaefer, et al.). These unfiltered images are calibrated relative to USNO-B1.0 (R). Further analysis reveals a faint, late-rising counterpart at a position consistent with the XRT position reported in GCN 6496 (Stroh, et al.). At a midpoint of 2157 s after the burst (in a 600 s stacked image), the counterpart was at a peak magnitude of 18.4+/-0.1 at a position: 00:07:58.0 -29:45:19.4 (J2000) [uncertainty < 1"] The counterpart then faded below 19th magnitude by 6000 s post-burst. A jpeg image is available at http://www.rotse.net/images/gsb282003_3c041-050_key.jpg Note that the object marked 156 is the candidate in question.