相关论文: Cosmic Reionization Redux

The first generation (Pop-III) stars can ionize 1-10% of the universe by $z=15$, when the metal-enriched (Pop-II) stars may contribute negligibly to the ionization. This low ionization tail might leave detectable imprints on the large-scale…

We calibrate here cosmological radiative transfer simulation with ATON/RAMSES with a range of measurements of the Lyman alpha opacity from QSO absorption spectra. We find the Lyman alpha opacity to be very sensitive to the exact timing of…

Detections and non-detections of Lyman alpha (Ly$\alpha$) emission from $z>6$ galaxies ($<1$ Gyr after the Big Bang) can be used to measure the timeline of cosmic reionization. Of key interest to measuring reionization's mid-stages, but…

We present the first large-scale radiative transfer simulations of cosmic reionization, in a simulation volume of (100/h Mpc)^3, while at the same time capturing the dwarf galaxies which are primarily responsible for reionization. We…

Reducing the power on small scales relative to the `standard' LCDM model alleviates a number of possible discrepancies with observations, and is favored by the recent analysis of WMAP plus galaxy and Lyman-alpha forest data. Here, we…

Cosmological hydrodynamic simulations have significantly improved over the past several years, and we have already shown that the observed properties of Lyman-break galaxies (LBGs) at z=3 can be explained well by the massive galaxies in the…

We investigate the effect of Dark Stars (DSs) on the reionization history of the Universe, and the interplay between them and feedback due to Lyman-Werner (LW) radiation in reducing the Cosmic Microwave Background (CMB) optical depth to a…

Cosmic reionization is expected to be complex, extended and very inhomogeneous. Existing constraints at z~6 on the volume-averaged neutral hydrogen fraction, <x_HI>, are highly model-dependent and controversial. Constraints at z<6,…

Lyman limit systems (LLSs) are dense hydrogen clouds with high enough HI column densities to absorb Lyman continuum photons emitted from distant quasars. Their high column densities imply an origin in dense environments; however, the…

The inhomogeneous cosmological reionization process leaves tangible imprints in the intergalactic medium down to z=4-5. The Lyman-alpha forest flux power spectrum provides a potentially powerful probe of the epoch of reionization. With the…

We present constraints on cosmological and star formation parameters based on combining observations of the Wilkinson Microwave Anisotropy Probe (WMAP) and high-redshift quasars from the Sloan Digital Sky Survey (SDSS). We use a…

A self-consistent formalism to jointly study cosmic reionization and thermal history of the IGM is presented. The model implements most of the relevant physics governing these processes, such as the inhomogeneous IGM density distribution,…

We study the reionization history of the Universe in cosmological models with non-Gaussian density fluctuations, taking them to have a renormalized $\chi^2$ probability distribution function parametrized by the number of degrees of freedom,…

We investigate Lyman-$\alpha$ transmission spikes at $z > 5$ in synthetic quasar spectra, and discuss their connection to the properties of the intergalactic medium and their ability to constrain reionization models. We use state-of-the-art…

Large-scale polarization of the cosmic microwave background measured by the WMAP satellite requires a mean optical depth to Thomson scattering, tau_e ~ 0.17. The reionization of the universe must therefore have begun at relatively high…

We examine the constraints on the epoch of reionization (redshift z_r) set by recent WMAP-3 observations of tau_e = 0.09 +/- 0.03, the electron-scattering optical depth of the cosmic microwave background (CMB), combined with models of…

Understanding the sources responsible for reionizing the Universe is a key goal of observational cosmology. A discrepancy has existed between the metagalactic hydrogen ionization rate, Gamma_HI, predicted by early hydrodynamical simulations…

We use a semi-analytical model to study the impact of reionization, and the associated radiative feedback, on galaxy formation. Two feedback models have been considered: (i) a standard prescription, according to which star formation is…

We use a compilation of cosmic microwave anisotropy data to constrain the epoch of reionization in the Universe, as a function of cosmological parameters. We consider spatially-flat cosmologies, varying the matter density $\Omega_0$ (the…

Models of the reionization and reheating of the intergalactic medium (IGM) at redshifts $z \gtrsim 6$ continue to grow more sophisticated in anticipation of near-future 21-cm, cosmic microwave background, and galaxy survey measurements.…