The angular correlation function and hierarchical moments of ∼70000 faint galaxies to R=23.5

We investigate the angular correlation function, omega(theta), and third- and fourth-order hierarchical moments of a large sample of similar to 70000 galaxies with apparent magnitudes 18.5 less than or equal to R less than or equal to 23.5. The data consist of 47 red-band INT Wide Field Camera CCD images, forming two widely separated fields of total areas 1.01 and 0.74 deg(2). Galaxy clustering is detected with a high significance of similar to 10 sigma. Over the R = 21 to 23.5 range of magnitude limits, the angular correlation functions approximately follow theta(-0.8) power laws at theta > 5 arcsec, with amplitudes consistent with previous surveys and best fitted by a luminosity evolution model in which galaxy clustering is approximately stable in proper coordinates (epsilon = 0). Assuming the redshift distribution from our pure luminosity evolution (PLE) model and the present-day galaxy correlation radii from Loveday et al., we estimate the clustering evolution as epsilon = 0.02(-0.31)(+0.48) for both fields combined, or epsilon = -0.29(-0.27)(+0.31) for the larger of the two fields which is thought to be the better in data quality. On the larger of our fields, omega(theta) at 2 less than or equal to theta less than or equal to 5 significantly exceeds a omega(theta) proportional to theta(-0.8) power law of the amplitude measured at theta > 5 arcsec. if this excess of close pairs is due to interacting and merging galaxies, we estimate that it is consistent with the local fraction of galaxies in close (<19 h(-1) kpc) pairs combined with a merger/interaction rate evolving as (1 + z)(m) with m = 2.01(-0.69)(+0.52). We derive the hierarchical moments s(3)(theta) and s(4)(theta) from the counts-in-cells of the 18.5 less than or equal to R less than or equal to 23.5 galaxies. We find relatively steep slopes of approximately theta(-0.4) for s(3)(theta) and theta(-0.6) for s(4)(theta), Similar to those of the hierarchical moments of 17 less than or equal to theta less than or equal to 20 galaxies in the EDSGCS at comparable physical scales. The s(3)(theta) and s(4)(theta) of the 18.5 less than or equal to R less than or equal to 23.5 galaxies show only a small reduction in normalization relative to those of the less deep EDSGCS survey, consistent with the expectations from N-body simulations of the evolving mass distribution. This indicates there is little change in the mean linear or non-linear biasing of galaxies from z similar to 0 to similar to 1, and hence appears to favour luminosity evolution for galaxies over 'transient starburst dwarf' models, and supports the interpretation of the stable galaxy clustering as evidence for a low-Omega universe.