GCN Circular 13606
W. Fong, R. Chornock, and E. Berger (Harvard) report: "We re-observed the location of the short-duration GRB 120804A (GCN 13573) with the Gemini Multi-Object Spectrograph (GMOS) mounted on the Gemini-North 8-meter telescope to check for the presence of a fading optical source. We obtained 16x180-sec of i-band observations in good seeing conditions (FWHM=0.65") starting on 2012 August 07.30 UT, 3.3 days after the BAT trigger and 3.0 days after our initial observations (GCN 13586). Digital image subtraction of the two GMOS epochs using the ISIS software package reveals a fading source slightly offset from the center of S1, suggesting this to be the optical afterglow of GRB 120804A. There are no additional residuals in or around the refined XRT position (improved upon from GCN 13577; http://www.swift.ac.uk/xrt_positions/00529686/). Both S1 and S2 appear to be extended, indicating that S1 is likely to be the host galaxy of GRB 120804A and S2 is likely unrelated to the GRB. We thank the Gemini staff for their assistance with these observations."