Evolution and Color Dependence of the Galaxy Angular Correlation Function: 350,000 Galaxies in 5 Square Degrees

When applied to deep photometric catalogs, the two-point angular correlationfunction, w(theta), is a sensitive probe of the evolution of galaxy clusteringproperties. Here we present measurements of w(theta) as a function of I_ABmagnitude and (R-I) color to a depth of I_AB=24, using a sample of ~350,000galaxies covering 5 degrees^2 in total over 5 separate fields. Using redshiftsof 3319 galaxies in early DEEP2 Galaxy Redshift Survey data, we constructrobust galaxy redshift distributions as a function of I_AB and R_AB magnitudeand (R-I) color for galaxies between 01 to z=0. A model in which the comoving scale-length, x_0,evolves linearly with redshift, x_0(z)=x_0(0)(1-Bz), fits the data better thanthe 'epsilon' model proposed by Groth and Peebles (1977). The clusteringproperties depend strongly on observed (R-I) color, with both the reddest andbluest galaxies exhibiting large clustering amplitudes and steeper slopes.Different observed (R-I) color ranges are sensitive to very disparate redshiftregimes. Red galaxies with (R-I)~1.5 lie in a narrow redshift range centered atz~0.85 and have a comoving scale length of clustering at z=0.85 of x_0=5.0+/-0.3 Mpc/h. These galaxies have early-type spectra and are likely progenitorsof massive local ellipticals. The bluest galaxies with (R-I)~0 appear to be amix of star-forming galaxies, both relatively local (z~0.3-0.6) dwarfs andbright z>1.4 galaxies, and broad-line AGN. We find that local blue dwarfs arerelatively unclustered, with x_0=1.6 +/-0.2 Mpc/h. The z>1.4 blue galaxies havea larger clustering scale-length, x_0>5 Mpc/h.Comment: 23 pages, 17 figures, accepted for publication in Ap