On the spatial correlations of Lyman break galaxies

Motivated by the observed discrepancy between the strong spatial correlations of Lyman break galaxies (LBGs) and their velocity dispersions, we consider a theoretical model in which these starbursting galaxies are associated with dark matter halos that experience an appreciable infall of material. Using numerical simulations, we show that selecting halos that substantially increase in mass within a fixed time interval introduces a "temporal bias" that boosts their clustering above that of the underlying population. If time intervals consistent with the observed LBGs' star formation rates of ∼50 M_⊙ yr^-1 are chosen, then spatial correlations are enhanced by up to a factor of 2. These values roughly correspond to the geometrical bias of objects 3 times as massive. Thus, it is clear that temporal biasing must be taken into account when interpreting the properties of LBGs.