The 2-point angular correlation function of 20,000 galaxies to V<23.5 and I<22

Abstract

The UH8K wide field camera of the CFHT was used to image 0.68 deg^2 of sky. From these images, ~20,000 galaxies were detected to completeness magnitudes V<23.5 and I<22.5. The angular correlation function of these galaxies is well represented by the parameterization omega(theta) = A_W*theta^-delta. The slope delta=-0.8 shows no significant variation over the range of magnitude. The amplitude A_W decreases with increasing magnitude in a way that is most compatible with a Lambda-CDM model (Omega_0 = 0.2, Lambda=0.8) with a hierarchical clustering evolution parameter epsilon>0. We infer a best-fit spatial correlation length of r_00= 5.85+/-0.5 h^-1 Mpc at z=0. The peak redshift of the survey (I<22.5) is estimated to be z_peak~0.58, using the blue-evolving luminosity function from the CFRS and the flat Lambda cosmology, and r_0(z_peak)=3.5+/-0.5 h^-1 Mpc. We also detect a significant difference in clustering amplitude for the red and blue galaxies, quantitatively measured by correlation lengths of r_00=5.3+/-0.5 h^-1 Mpc and r_00=1.9+/-0.9 h^-1 Mpc respectively, at z=0.