TITLE: GCN CIRCULAR NUMBER: 11815 SUBJECT: GRB 110319B: GROND upper limits DATE: 11/03/20 15:19:22 GMT FROM: Jochen Greiner at MPI A. Updike (GSFC), J. Greiner, T. Kruehler, F. Schrey (all MPE Garching), A. Nicuesa Guelbenzu and S. Klose (both TLS Tautenburg) report on behalf of the GROND team. We observed the field of GRB 110319B (GBM trigger 322256044 at 19:34:02 UT; Swift slew source, Cummings et al., GCN #11813) 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). Observation started at 08:24 UT, which is 12.9 h after the trigger, and were obtained under clear skies with an airmass of around 2.0 and seeing of 1.6". In stacked images with a total integration time of 25 min in g'r'i'z and 20 min in JHK (mid-time 9:12 UT), we do not detect a source in the 2.4" XRT error circle of the X-ray counterpart candidate (Sbarufatti et al., GCN #11814) to the following 3-sigma upper limits (AB system): g' > 23.1 r' > 23.2 i' > 23.2 z' > 23.2 J > 21.1 H > 20.5 These magnitudes are calibrated against GROND zeropoints and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998). GROND is currently cooling down after hardware maintenance, and hence no proper K band data are available for this burst.