GCN Circular 14048
W. Fong (Harvard), D. Fox (PSU), E. Berger and R. Chornock (Harvard) report: "We observed the location of GRB 121209A (Maselli et al., GCN14045) with the Gemini Multi-Object Spectrograph (GMOS) mounted on the Gemini-South 8-meter telescope starting on 2012 Dec 10.028 UT (2.68 hr after the BAT trigger). We obtained 60-sec in each of the r- and i-bands in 0.75" seeing. We do not detect any optical source within the XRT position reported in GCN 14045, nor within the latest reported position ( http://www.swift.ac.uk/xrt_unenh_positions/00540964/). Calibrated to stars in the SDSS DR8 field, we place 3-sigma limits of r > 22.6 mag and i > 23.0 mag on the optical afterglow of GRB 121209A at 2.7 hr after the burst (uncorrected for Galactic extinction in the direction of the burst). We thank the Gemini staff for their assistance with these observations."