A Possible Effect of the Period of Galaxy Formation on the Angular Correlation Function

During the epoch of galaxy formation, the formation of the first galaxies inregions of high overdensity may lead to an initial amplitude of the spatialcorrelation function of galaxies, $\xi_0,$ much higher than that expected inlinear perturbation theory. This initially high ``bias'' would consequentlydecrease to the near-unityvalues expected from local observations. Such a``Decreasing Correlation Period'' (DCP), detected in N-body simulations undercertain conditions by several authors, is parametrised in a simple way, endingat a ``transition'' redshift $z_t.$ Consequences on $w_0,$ the amplitude of theangular correlation function of faint galaxies (for a fixed apparent magnituderange), have been estimated. The sensitivity of $w_0$ to $z_t,$ and how this isaffected by the redshift distribution of the galaxies in the sample, by lowredshift spatial correlation function behaviour, by cosmology, and by the rateat which $\xi_0$ decreases during the DCP, are shown and discussed. This simplemodel is intended as a first exploration of the effects of the DCP for a likelyrange of parameter space. Comparison with the Hubble Deep Field (HDF) estimateof $w_0$ (Villumsen et al. 1996) indicates that the DCP is compatible withobservation for values of $z_t$ in the theoretically expected range $z_t\gtapprox 1.$ However, tighter observational constraints on the HDF redshiftdistribution and on low redshift correlation function growth will be neededeither to detect the DCP unambiguously or to constrain $z_t$ to redshiftsgreater than those of galaxies in existing surveys.Comment: 5 pages, LaTeX format, AAS macros, to appear in Astrophysical Journal, 20 Jul