The clustering of massive galaxies at z similar to 1

We use the angular two-point correlation function to estimate the spatial correlation length of radio sources taken from the large-area 1.4 GHz NVSS radio survey. At the median survey redshift of z similar to 1, r(0) is found to be increasing with flux density. This is consistent with a scenario in which powerful (i.e. FRII) radio galaxies probe significantly more massive spatial structures than less powerful radio galaxies. The large spatial correlation length that we derive for FRIIs is remarkably close to that of extremely red objects (EROs). This implies that powerful radio galaxies and EROs trace equally massive structures at z similar to 1. Moreover, because powerful radio galaxies and EROs are both associated with luminous early-type galaxies we propose that they could be the same objects seen at different evolutionary stages. The correlation length of massive, luminous galaxies at z similar to 1 is comparable to that of bright ellipticals locally, suggesting that r(0) (comoving) of these massive galaxies has changed little from z similar to 1 to z approximate to 0. This is in excellent agreement with current ACDM hierarchical model predictions