Massive, red galaxies in a hierarchical universe - II. Clustering of Extremely Red Objects

We present predictions for the clustering of Extremely Red Objects (EROs) in a Lambda cold dark matter universe, using a semi-analytical galaxy formation model in combination with a cosmological N-body simulation. EROs are red, massive galaxies observed at 0.7 less than or similar to z less than or similar to 3, and their numbers and properties have posed a challenge to hierarchical galaxy formation models. We analyse the halo occupation distribution and two-point correlation function of EROs, exploring how these quantities change with apparent magnitude, colour cut and redshift. Our model predicts a halo occupation distribution that is significantly different from that typically assumed. This is due to the inclusion of active galactic nuclei (AGN) feedback, which changes the slope and scatter of the luminosity-host halo mass relation above the mass where AGN feedback first becomes important. We predict that, on average, dark matter haloes with masses above 10(13) h(-1)M(circle dot) host at least one ERO at 1.5 <= z <= 2.5. Taking into account sample variance in observational estimates, the predicted angular clustering for EROs with either (R - K) > 5 or (i - K) > 4.5 is in reasonable agreement with current observations.