The 2dF QSO Redshift Survey - II. Structure and evolution at high redshift

Abstract

We present a clustering analysis of QSOs over the redshift range z=0.3-2.9. We use a sample of 10558 QSOs taken from the preliminary catalogue of the 2dF QSO Redshift Survey (2QZ). The two-point redshift-space correlation function of QSOs is shown to follow a power law on scales s~1-35h-1Mpc. Fitting a power law to QSO clustering averaged over the redshift interval 0.3 99 per cent confidence level). A redshift dependent bias is required to reconcile QSO clustering observations with theory. A simple biasing model, in which QSOs have cosmologically long lifetimes (or alternatively form in peaks above a constant threshold in the density field) is acceptable in an EdS cosmology, but is only marginally acceptable if Omega_0=0.3 and lambda_0=0.7. Biasing models which assume QSOs form over a range in redshift, based on the Press-Schechter formalism are approximately consistent with QSO clustering evolution (abridged).