GCN Circular 12366
J. Elliott (MPE Garching), T. Kruehler (DARK/NBI), S. Klose, D. A. Kann (both TLS Tautenburg), A. Rau and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of the IPN GRB 110918A (Hurley et al., GCN 12357) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile). Observations started at September 20, 2011, 02:37 which is roughly 29.2 hr after the trigger. They consisted of a dithered mosaic of 5 tiles covering the full IPN error box. The X-ray and optical afterglow candidate reported by Mangano et al. (GCN #12364) and Tanvir et al. (GCN #12365) however is only covered by the larger field of view of the NIR channels. We confirm the presence of a bright NIR source, and estimate a preliminary AB magnitude of J = 18.7 +/- 0.1 at a midtime of 08:04 UT, which has been derived by calibrating the field against stars from the 2MASS catalog.