2004ApJ...617..765C

When applied to deep photometric catalogs, the two-point angular correlation function, ω(θ), is a sensitive probe of the evolution of galaxy clustering properties. Here we present measurements of ω(θ) as a function of I_ABmagnitude and (R-I) color to a depth of I_AB=24 on scales θ=7''-3', using a sample of ∼350,000 galaxies covering 5 deg² in total over five separate fields. Using redshifts of 2954 galaxies in early DEEP2 Galaxy Redshift Survey data, we construct robust galaxy redshift distributions as a function of I_ABmagnitude and (R-I) color for galaxies in the range 0<z<2. We constrain models of the redshift evolution of galaxy clustering and find that significant growth of clustering has occurred from z≥1 to z=0. A model in which the comoving scale length, x₀, evolves linearly with redshift, x₀(z)=x₀(0)(1-Bz), fits the data better than the ε model proposed by Groth & Peebles. The clustering properties depend strongly on observed (R-I) color, with both the reddest and bluest galaxies exhibiting large clustering amplitudes and steeper slopes. Different observed (R-I) color ranges are sensitive to very disparate redshift regimes. Red galaxies with (R-I)∼1.5 lie in a narrow redshift range centered at z∼0.85 and have a comoving scale length of clustering at z=0.85 of x₀=5.0±0.3/h^–1 Mpc. These galaxies have early-type spectra and are likely progenitors of massive local ellipticals. The bluest galaxies with (R-I)∼0 appear to be a mix of star-forming galaxies, both relatively local (z∼0.3-0.6) dwarfs and bright z>1.4 galaxies, as well as broad-line active galactic nuclei. We find that local blue dwarfs are relatively unclustered, with x₀=1.6±0.2 h^–1 Mpc. The z>1.4 blue galaxies have a larger clustering scale length, x₀≳5 h^–1 Mpc.