TITLE: GCN CIRCULAR NUMBER: 8975 SUBJECT: GRB 090309A: GROND upper limits DATE: 09/03/11 00:24:38 GMT FROM: Adria C. Updike at Clemson U A. C. Updike (Clemson University), C. Clemens, and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of the possibly short/hard GRB 090309 (Swift trigger 345945; Evans et al., GCN #8964) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile). Observations started at 07:22 UT on March 10th, 7.9 hours after the GRB trigger and continued for 2.5 hours at an average seeing of 1.5" and an average airmass of 1.5. In one hour of stacked exposures, we do not detect a source within the Swift-XRT enhanced error circle (Goad et al., GCN #8969) down to g' > 23.4, r' > 23.8, i' > 23.2, z' > 23.0, J > 21.3, H > 21.0 and K > 20.3 The given limits in the AB system are derived based on calibrating the images against GROND zeropoints and 2MASS field stars and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.23 in the direction of the burst (Schlegel et al. 1998).