Two-point correlation function of high-redshift objects: an explicit formulation on a light-cone hypersurface

Abstract

While all the cosmological observations are carried out on a light-cone, the null hypersurface of an observer at z=0, the clustering statistics has been properly defined only on the constant-time hypersurface. We develop a theoretical formulation for a two-point correlation function on the light-cone, and derive a practical approximate expression relevant to the discussion of clustering of high-redshift objects at large separations. As a specific example, we present predictions of the two-point correlation function for the Durham/AAT, SDSS and 2dF quasar catalogues. We also briefly discuss the effects of adopted luminosity function, cosmological parameters and bias models on the correlation function on the light-cone.