A constant clustering amplitude for faint galaxies?

The angular clustering of faint field galaxies is investigated using deep imaging (I similar to 25) obtained with the 10 m Keek I telescope. The autocorrelation function is consistent with omega(theta) proportional to theta(-0.8), and although less steep correlation functions cannot be ruled out with high confidence, we find no compelling evidence for a systematic decrease in the power-law index at the faintest magnitude limits. Results from a number of independent observational studies are combined in order to investigate the variation of the correlation amplitude with median I magnitude. At I-med similar to 23, the results obtained by different studies are all in rough agreement and indicate that for (I-med > 22 the correlation amplitude declines far less steeply than would be expected from an extrapolation of the trend in the brighter samples. In particular, at I-med similar to 24, our data indicate omega(theta) to be a factor of similar to 7 higher than the extrapolation. A near independence of magnitude is a general feature of the correlation amplitude in models in which the redshift distribution of the faint field population contains a substantial fraction of galaxies with z greater than or similar to 1. In order to reproduce the apparent abrupt flattening of the amplitude of omega(theta) observed at faint limits, approximately 50% of the galaxies in a sample with a depth of I similar to 25 must be at z > 1.