Modeling Galaxy Clustering with Cosmological Simulations

Abstract

I review recent progress in understanding and modeling galaxy clustering in cosmological simulations, with emphasis on models based on high-resolution dissipationless simulations. During the last decade, significant advances in our understanding of abundance and clustering of dark matter halos allowed construction of accurate, quantitative models of galaxy clustering both in linear and non-linear regimes. Results of several recent studies show that dissipationless simulations with a simple, non-parametric model for the relation between halo circular velocity and luminosity of the galaxy they host predict the shape, amplitude, and luminosity dependence of the two-point correlation function in excellent agreement with the observed galaxy clustering in the SDSS data at z~0 and in the DEEP2 samples at z~1 over the entire probed range of projected separations. In particular, the small-scale upturn of the correlation function from the power-law form in the SDSS and DEEP2 luminosity-selected samples is reproduced very well. At z~3-5, predictions also match the observed shape and amplitude of the angular two-point correlation function of Lyman-break galaxies (LBGs) on both large and small scales, including the theoretically predicted strong upturn at small scales. This suggests that, like galaxies in lower redshift samples, the LBGs are fair tracers of the overall halo population and that their luminosity is tightly correlated with the circular velocity (and hence mass) of their dark matter halos.