Distribution of the redshifts of the cluster and the nearby galaxies. Left: Sky distribution of galaxies in the cluster Abell 7 with 0.095 < z < 0.115. The large blue circle shows the r₅₀₀ for the cluster as described in the text, and the small red circle indicates a 2 arcmin (∼250 kpc) radius around the host of J0011+3217. Note that a bright star at the bottom right of the plot may prevent the detection of galaxies in this area. Right: Histogram of the redshifts in the left panel, with galaxies within r₅₀₀ highlighted in blue and those close to the radio source in red. If some or all of the galaxies close to the radio source form a group, the group has a systematic velocity offset with respect to the cluster.