Observations of Galaxy Clustering at High Redshift

This paper reviews the current status of measurements of galaxy clustering at high redshifts (z > ∼ 0.3). The focus is on the inherent limitations in the observation and interpretation of the “evolution of clustering”. It is likely that results from the first attempts to characterize galaxy clustering beyond the “local” universe have been significantly limited by sample variance, as the difficulty in assembling large samples over large volumes is exacerbated as the observations become more challenging. It is also argued that, because of the complicated relationship between galaxies and mass (i.e., bias), and the surprising degeneracies among different popular cosmological models, it is likely that studies of galaxy clustering as a function of cosmic epoch will never be useful for strong discrimination between different cosmological models. On the other hand, observations of galaxy clustering are capable of testing basic ideas about how (and where) galaxies form. Galaxy formation, as opposed to cosmography, will probably remain a fundamental question even beyond the MAP and Planck era.