Clustering properties of a type-selected volume-limited sample of galaxies in the CFHTLS

Abstract

We present an investigation of the clustering of the faint (i � < 24.5) field galaxy population in the redshift range 0.2 < z < 1.2. Using 100 000 precise photometric redshifts extracted from galaxies in the four ultra-deep fields of the Canada-France Legacy Survey, we construct a set of volume-limited galaxy samples. We use these catalogues to study in detail the dependence of the amplitude Aw and slope δ of the galaxy correlation function w on absolute MB rest-frame luminosity, redshift, and best-fitting spectral type (or, equivalently, rest-frame colour). Our derived comoving correlation lengths for magnitude-limited samples are in excellent agreement with measurements made in spectroscopic surveys. Our main conclusions are as follows: 1. the comoving correlation length for all galaxies with −19 < MB − 5l ogh < −22 declines steadily from z ∼ 0. 3t oz ∼ 1; 2. at all redshifts and luminosity ranges, galaxies with redder rest-frame colours have clustering amplitudes from two and three times higher than bluer ones; 3. for both the red and blue galaxy populations, the clustering amplitude is invariant with redshift for bright galaxies (−19 < MB − 5l ogh < −22); 4. at z ∼ 0.5 for less luminous galaxies with MB − 5l ogh ∼− 19 we find higher clustering amplitudes of ∼6 h −1 Mpc; 5. the relative bias between redder and bluer rest-frame populations increases gradually towards fainter magnitudes. Among the most important implications of these results is that although the full galaxy population traces the underlying dark matter distribution quite well (and is therefore quite weakly biased), redder, older galaxies have clustering lengths that are almost invariant with redshift are quite strongly biased by z ∼ 1.