A Counts‐in‐Cells Analysis of Lyman‐Break Galaxies at Redshiftz∼ 3

We have measured the counts-in-cells fluctuations of 268 Lyman-break galaxies with spectroscopic redshifts in six 9' × 9' fields at z ~ 3. The variance of galaxy counts in cubes of comoving side length 7.7, 11.9, 11.4 h 100 −1 Mpc is σ gal 2 ~1.3±0.4 for Ω M = 1, 0.2 open, 0.3 flat, implying on these scales a bias of σ gal /σ mass = 6.0 ± 1.1, 1.9 ± 0.4, and 4.0 ± 0.7. The bias and abundance of Lyman-break galaxies are surprisingly consistent with a simple model of structure formation that assumes only that galaxies form within dark matter halos, that Lyman-break galaxies' rest-UV luminosities are tightly correlated with their dark masses, and that matter fluctuations are Gaussian and have a linear power-spectrum shape at z ~ 3 similar to that determined locally (Γ ~ 0.2). This conclusion is largely independent of cosmology or spectral normalization σ 8 . A measurement of the masses of Lyman-break galaxies would in principle distinguish between different cosmological scenarios.