Radio Galaxy Clustering at z ∼ 0.3

Radio galaxies are uniquely useful as probes of large-scale structure as their uniform identification with giant elliptical galaxies out to high redshift means that the evolution of their bias factor can be predicted. As the initial stage in a project to study large-scale structure with radio galaxies we have performed a small redshift survey, selecting 29 radio galaxies in the range 0.19 < z < 0.45 from a contiguous 40 deg area of sky. We detect significant clustering within this sample. The amplitude of the two-point correlation function we measure is consistent with no evolution from the local (z < 0.1) value. This is as expected in a model in which radio galaxy hosts form at high redshift and thereafter obey a continuity equation, although the signal:noise of the detection is too low to rule out other models. Larger surveys out to z ∼ 1 should reveal the structures of superclusters at intermediate redshifts and strongly constrain models for the evolution of large-scale structure. Subject headings: large-scale structure of the Universe — galaxies: active — surveys