GCN Circular 11809
T. Kruehler, J. Greiner, F. Schrey (all MPE Garching), and S. Klose (TLS Tautenburg) report on behalf of the GROND team. We observed the field of GRB 110318B (Swift trigger 449549; Margutti et al., GCN #11800 simultaneously in g'r'i'z' with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observation started at 07:40 UT, which is 16.2 h after the trigger, and were obtained under clear skies with an airmass of around 1.1 and seeing of 1" In stacked images with a total integration time of 25 min, we do not detect a source in the refined XRT error circle (Evans et al., GCN #11803) to the following upper limits (AB system): g' > 23.7 r' > 23.6 i' > 23.6 z' > 23.4 Given magnitudes are calibrated against GROND zeropoints and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.46 mag in the direction of the burst (Schlegel et al. 1998). GROND is currently undergoing hardware maintenance, and hence no NIR data are available for this burst.