The first stars form in dark matter halos of masses ∼10M⊙ as suggested by an increasing number of numerical simulations. Radiation feedback from these stars expels most of the gas from their shallow potential well of their surrounding dark matter halos. We use cosmological adaptive mesh refinement simulations that include self-consistent Population III star formation and feedback to examine the...

We have investigated the effects of AGN outflows on the amplitude of the matter power spectrum in a simple model of spherically symmetric outflows around realistically clustered AGN population. We find that two competing effects influence the matter power spectrum in two opposite directions. First, AGN outflows move baryons from high to low density regions, decreasing the amplitude of the matte...

We have performed high-resolution hydrodynamic simulations of the Lyα forest in a variety of popular cold dark matter dominated cosmologies, including a low density and a vacuum-dominated model. The fluctuation amplitude of these models is chosen to match the observed abundance of galaxy clusters at low redshift. We assume that the intergalactic medium is photoionized and photoheated by a unifo...

We assess supernova (SN)–driven pregalactic outflows as a mechanism for distributing the product of stellar nucleosynthesis over large cosmological volumes prior to the reionization epoch. SN ejecta will escape the grasp of halos with virial temperatures Tvir ∼ 10K (corresponding to masses M ∼ 10 h M⊙ at redshift z = 9 when they collapse from 2–σ fluctuations) if rapid cooling can take place, a...

We measure the matter power spectrum from 31 Lyα spectra spanning the redshift range of 1.6-3.6. The optical depth, τ , for Lyα absorption of the intergalactic medium is obtained from the flux using the inversion method of Nusser & Haehnelt (1999). The optical depth is converted to density by using a simple power law relation, τ ∝ (1 + δ) α. The non-linear 1D power spectrum of the gas density i...