Galaxy Clustering Evolution in the CNOC2 High‐Luminosity Sample

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Abstract
The redshift evolution of the galaxy two-point correlation function is a fundamental cosmological statistic. To identify similar galaxy populations at different redshifts, we select a strict volume-limited sample culled from the 6100 cataloged Canadian Network for Observational Cosmology field galaxy redshift survey (CNOC2) galaxies. Our high-luminosity subsample selects galaxies having k-corrected and evolution-compensated R luminosities, M, above -20 mag (H0 = 100 km s-1 Mpc-1 ), where M(R) -20.3 mag. This subsample contains about 2300 galaxies distributed between redshifts 0.1 and 0.65 spread over a total of 1.55 deg2 of sky. A similarly defined low-redshift sample is drawn from the Las Campanas Redshift Survey. We find that the comoving two-point correlation function can be described as ξ(r|z) = (r00/r)γ(1 + z)-(3+-γ), with r00 = 5.03 ± 0.08 h-1 Mpc, = -0.17 ± 0.18, and γ = 1.87 ± 0.07 over the z = 0.03-0.65 redshift range, for ΩM = 0.2 and Λ = 0. The measured clustering amplitude and its evolution are dependent on the adopted cosmology. The measured evolution rates for ΩM = 1 and flat ΩM = 0.2 background cosmologies are = 0.80 ± 0.22 and = -0.81 ± 0.19, respectively, with r00 = 5.30 ± 0.1 and 4.85 ± 0.1 h-1 Mpc, respectively. The sensitivity of the derived correlations to the evolution corrections and details of the measurements is presented. The analytic prediction of biased clustering evolution for only the low-density, ΛCDM cosmology is readily consistent with the observations, with biased clustering in an open cosmology somewhat marginally excluded and a biased ΩM = 1 model predicting clustering evolution that is more than 6 standard deviations from the measured value.

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