We present clustering results from the 2dF QSO Redshift Survey ( 2QZ ) which currently contains over 20,000 QSOs at z < 3 .
The two-point correlation function of QSOs averaged over the entire survey ( \bar { z } \simeq 1.5 ) is found to be similar to that of local galaxies .
When sub-dividing the sample as a function of redshift , we find that for an Einstein-de Sitter universe QSO clustering is constant ( in comoving coordinates ) over the entire redshift range probed by the 2QZ , while in a universe with \Omega _ { 0 } = 0.3 and \lambda _ { 0 } = 0.7 there is a marginal increase in clustering with redshift .
Sub-dividing the 2QZ on the basis of apparent magnitude we find only a slight difference between the clustering of QSOs of different apparent brightness , with the brightest QSOs having marginally stronger clustering .
We have made a first measurement of the redshift space distortion of QSO clustering , with the goal of determining the value of cosmological parameters ( in partcular \lambda _ { 0 } ) from geometric distortions .
The current data do not allow us to discriminate between models , however , in combination with constraints from the evolution of mass clustering we find \Omega _ { m } = 1 - \lambda _ { 0 } = 0.23 ^ { +0.44 } _ { -0.13 } and \beta ( z \sim 1.4 ) = 0.39 ^ { +0.18 } _ { -0.17 } .
The full 2QZ data set will provide further cosmological constraints .