The three-point correlation function of luminous red galaxies in the Sloan Digital Sky Survey

Abstract

We present measurements of the redshift-space three-point correlation function of 50 967 luminous red galaxies (LRGs) from Data Release 3 (DR3) of the Sloan Digital Sky Survey (SDSS). We have studied the shape dependence of the reduced three-point correlation function on three different scales, and, and over the range of and. On small scales is nearly constant, with little change as a function of q and θ. However, there is evidence for a shallow U-shaped behaviour (with θ) which is expected from theoretical modelling of. On larger scales (and), the U-shaped anisotropy in (with θ) is more clearly detected. We compare this shape dependence in with that seen in mock galaxy catalogues which were generated by populating the dark matter haloes in large N-body simulations with mock galaxies using various halo occupation distributions (HOD). We find that the combination of the observed number density of LRGs, the (redshift-space) two-point correlation function and provides a strong constraint on the allowed HOD parameters and breaks key degeneracies between these parameters. For example, our observed disfavours mock catalogues that overpopulate massive dark matter haloes with many LRG satellites. We also estimate the linear bias of LRGs to be in excellent agreement with other measurements. © 2007 The Authors. Journal compilation © 2007 RAS.