THE CANADA-FRANCE REDSHIFT SURVEY. VIII. EVOLUTION OF THE CLUSTERING OF GALAXIES FROM z～1

摘要

This paper analyzes the spatial clustering of galaxies in the Canada-France Redshift Survey (CFRS). We have used the projected two-point correlation function, w(r_p), to investigate the spatial distribution of the 591 galaxies with secure redshifts between 0 ≤ z ≤ 1.3 in the five CFRS fields. The slope of the two-point correlation function for the sample as a whole is γ = 1.64 ± 0.05, very similar to the local slope, and γ is therefore not strongly evolving with redshift. However, the amplitude of the correlation function decreases strongly with increasing redshift, so that at z ≈ 0.6 it is a factor of 10 lower (for q_0 = 0.5) than for a similarly selected local galaxy population, on scales 0.1 < r < 2 h~(-1) Mpc (q_0 = 0.5). As a whole, the CFRS data are adequately represented by r_0(z = 0.53) = 1.33 ± 0.09 h~(-1) Mpc for q_0 = 0.5, and r_0(z = 0.53) = 1.57 ± 0.09 h~(-1) Mpc for q_0 = 0. Unless the galaxy population at high redshift is quite different from any population seen locally, an unlikely possibility, then this implies growth of clustering as described by the evolutionary parameter ε to be in the range 0 < ε < +2. No difference in the clustering of red and blue galaxies is seen at z ≥ 0.5, although at lower redshifts, 0.2 ≤ z ≤ 0.5, blue galaxies are somewhat less strongly correlated than the redder galaxies, as seen in local samples. This effect could be the equivalent for field galaxies to the Butcher-Oemler effect seen in clusters of galaxies. The cross-correlation functions between red and blue samples have comparable amplitudes to the autocorrelation functions of each. The distribution and power spectrum of pair separations does not indicate significant periodic patterns in the distribution of galaxies along the lines of sight. Finally, the densest structures in the survey are identified and characterized, including the structure at z = 0.985 in the 1415 + 52 field, reported previously, and a new cluster of galaxies at z = 0.78 in the 1000 + 25 field.