Angular momentum and clustering properties of early dark matter haloes

Abstract

In this paper, we study the angular momentum properties of simulated dark matter haloes at high redshifts that likely host the first stars in the Universe. Calculating the spin distributions of these 106- 10 7 M⊙ haloes in redshift slices from z = 15 to 6, we find that they are well fit by a lognormal distribution as is found for lower redshift and more massive haloes in earlier work. We find that both the mean value of the spin and dispersion are largely unchanged with redshift for all haloes. Our key result is that subsamples of low- and high-spin, 106 and 107 M⊙, haloes show difference in clustering strength. In both mass bins, higher spin haloes are more strongly clustered in concordance with a tidal torquing picture for the growth of angular momentum in dark matter haloes in the cold dark matter paradigm. © 2009 RAS.