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

In this paper we present a clustering analysis of QSOs over the redshift range z 0:3-2:9: We use a sample of 10 558 QSOs taken from the preliminary data release catalogue of the 2dF QSO Redshift Survey (2QZ). The two-point redshift-space correlation function of QSOs, j Q s; is shown to follow a power law on scales s . 1-35 h 21 Mpc: Fitting a power law of the form j Q s s/ s 0 2g to the QSO clustering averaged over the redshift interval 0:3 , z # 2:9; we find s 0 3:99 10:28 20:34 h 21 Mpc and g 1:58 10:10 20:09 for an Einstein-de Sitter cosmology. The effect of a significant cosmological constant, l 0 , is to increase the separation of QSOs, so that with V 0 0:3; l 0 0:7 the power law extends to .60 h 21 Mpc and the best fit is s 0 5:69 10:42 20:50 h 21 Mpc and g 1:56 10:10 20:09 : These values, measured at a mean redshift of z 1:49; are comparable to the clustering of local optically selected galaxies. We compare the clustering of 2QZ QSOs with generic cold dark matter (CDM) models with shape parameter G eff . Standard CDM with G eff 0:5 is ruled out in both Einstein -de Sitter and cosmological constant dominated cosmologies, where G eff . 0:2-0:4 and G eff . 0:1-0:2 respectively are the allowable ranges.