EVOLUTION OF THE ANGULAR-CORRELATION FUNCTION

For faint photometric surveys, our ability to quantify the clustering of galaxies has depended on interpreting the angular correlation funct ion as a function of the limiting magnitude of the data. Because of th e broad redshift distribution of galaxies at faint magnitude limits, t he correlation signal has been extremely difficult to detect and inter pret. Here we introduce a new technique for measuring the evolution of clustering. We utilize photometric redshifts derived from multicolor surveys to isolate redshift intervals and to calculate the evolution o f the amplitude of the angular two-point correlation function. Applyin g these techniques to the Hubble Deep Field, we find that the shape of the correlation function at z = 1 is consistent with a power law with a slope of -0.8. For z > 0.4, the best fit to the data is given by a model of clustering evolution with a comoving r(0) = 2.37 h(-1) Mpc an d epsilon = -0.4(-0.65)(+0.37), which is consistent with published mea sures of the clustering evolution. To match the canonical value of r(0 ) = 5.4 h(-1) Mpc found for the clustering of local galaxies requires a value of epsilon = 2.10(-0.64)(+0.03) (significantly more than linea r evolution). The log likelihood of this latter fit is 4.15 times smal ler than that for the r(0) = 2.37 h(-1) Mpc model. We, therefore, conc lude that the parameterization of the clustering evolution of (1+2)(-( 3+epsilon)) is not a particularly good fit to the data.