Cosmological implications of Lyman-break galaxy clustering

We review our analysis of the clustering properties of "Lyman-break" galaxies (LBGs) at redshift z similar to 3, previously discussed in Wechsler et al. [6]. We examine the likelihood of spikes found by Steidel et al. [2] in the redshift distribution of LBGs, within a suite of models for the evolution of structure in the Universe. Using high-resolution dissipationless N-body simulations, we analyze deep pencil-beam surveys from these models in the same way that they are actually observed, identifying LBGs with the most massive dark matter halos. We find that all the models (with SCDM as a marginal exception) have a substantial probability of producing spikes similar to those observed, because the massive halos are much more clumped than the underlying matter - i.e., they are biased. Therefore, the likelihood of such a spike is not a good discriminator among these models. The LEG correlation functions are less steep than galaxies today (gamma similar to 1.4), but show similar or slightly longer correlation lengths. We have extended this analysis and include a preliminary comparison to the new data presented in Adelberger et al. [8]. We also discuss work in progress, in which we use semi-analytic models to identify Lyman-break galaxies within dark-matter halos.