The Angular Correlation Function and Hierarchical Moments of 70000 Faint Galaxies to R=23.5

Abstract

We investigate the angular correlation function, omega(theta), and third and fourth-order hierarchical moments of a survey with approx. 70000 faint galaxies detected on a total area 1.74 sq. deg. to a limit of R=23.5. The omega(theta) amplitudes and scaling with magnitude limit are most consistent with approximately stable clustering (epsilon=0). On the larger of our fields, the amplitude of omega(theta) is significantly higher at 2-5 arcsec separations than at >5 arcsec, indicating an excess of physically close galaxy pairs above the number expected from omega(theta) seen at larger scales. This is consistent with the number of interacting galaxy pairs seen locally combined with a merger/interaction rate evolving as (1+z)^m with m=2.01_{-0.69}^{+0.52}. We also estimate the hierarchical moments s_3 and s_4 from the galaxy counts-in-cells. For 18.5<R<23.5 galaxies, these have relatively steep slopes (approximately -0.4 for s_3 and -0.6 for s_4), similar to the hierarchical moments of 17<B<20 galaxies in the EDSGCS at the same physical scales, and show only a small reduction in normalization relative to the shallower survey. This implies that there is little change in the mean linear or non-linear biasing of the galaxy distribution out to z=1.

21 pages, latex, 16 figures, revised version submitted to MNRAS