Confronting cold dark matter cosmologies with strong clustering of Lyman break galaxies at $z\sim 3$

We perform a detailed analysis of the statistical significance of a concentration of Lyman break galaxies at $z\sim 3$ recently discovered by Steidel et al. (1997), using a series of N-body simulations with $N={256}^3$ particles in a $(100\text{himpc}{)}^3$ comoving box. While the observed number density of Lyman break galaxies at $z\sim 3$ implies that they correspond to systems with dark matter halos of $\text{simlt}{10}^{12}{M}_{\odot }$, the resulting clustering of such objects on average is not strong enough to be reconciled with the concentration if it is fairly common; we predict one similar concentration approximately per ($6\sim 10$) fields in three representative cold dark matter models. Considering the current observational uncertainty of the frequency of such clustering at $z\sim 3$, it would be premature to rule out the models, but the future spectroscopic surveys in a dozen fields could definitely challenge all the existing cosmological models a posteriori fitted to the $z=0$ universe.