GCN Circular 12454
M. Nardini (Uni. Milano-Bicocca), J. Elliott and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB111018A (Swift trigger 505801; Marhsal et al., GCN #12450) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observations started at 23:47 UT on 18 October 2011, 6.35 hours after the trigger. They were performed at an average seeing of 2.8 and at an average airmass of 1.9. Based on images with total exposures of 1500 s in g'r'i'z' and 1200 s in JHK, we do not detect a source within the Swift-XRT error circle reported by Goad et al. (GCN #12453) down to (all AB): g' > 23.2, r' > 23.5, i' > 22.5, z' > 22.2, J > 20.0, H > 18.9, K > 18.6 Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to the heavy reddening of E(B-V)=2.16 in the direction of the burst (Schlegel et al. 1998).