TITLE: GCN CIRCULAR NUMBER: 6686 SUBJECT: GRB 070729: LCO optical imaging DATE: 07/07/29 22:45:51 GMT FROM: Edo Berger at Carnegie Obs E. Berger, D. Murphy (Carnegie Observatories) report: "We imaged the position of the X-ray afterglow of GRB 070729 (GCNs #6681,6682) with the Swope 40-inch telescope at Las Campanas Observatory starting on 2007 July 29.385 UT. A total of 3600 sec were obtained in R-band. We do not detect any sources within the XRT error circle, including the possible host galaxy detected in K-band with Magellan (GCN #6680). The 3-sigma limit is R>21.8 mag, indicating that the putative host is red, with R-K>3.6 mag."