TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3589 SUBJECT: GRB050709 : Chandra source optical counterpart DATE: 05/07/13 12:35:11 GMT FROM: Brian Lindgren Jensen at U.of Copenhagen GRB050709.94 : Chandra source optical counterpart B. L. Jensen, U. G. Jørgensen, J. Hjorth, J. P. U. Fynbo, D. Watson, J. M. Castro Cerón, K. Pedersen, H. Pedersen, J. Sollerman (DARK Cosmology Centre, Niels Bohr Institute) "Using the Danish 1.54m+DFOSC (La Silla), we have obtained R-band images of the field of the SXC-source associated with GRB 050709.94 (Butler et al., GCN#3570) for two nights (July 11.3 and 12.3 UT) under good conditions (0.7" and 1.0" seeing, respectively). At the location of the Chandra source (Fox et al., GCN#3585), we clearly detect the object present on the DSS. In the image with the best seeing (the first night), this object resolves into two sources separated by about 1". The 0.5" Chandra error-circle covers the fainter, eastern-most, of these two sources. In the image from the second night, the objects are not clearly resolved. Aperture photometry of both objects together in the two epochs (at t+33h and t+56h) do not indicate significant R-band variability. Images of the objects are shown at: http://www.astro.ku.dk/~brian_j/grb/grb050709.94/ "