Cosmic Reionization Redux

  title={Cosmic Reionization Redux},
  author={Nickolay Y. Gnedin and Xiaohui Fan},
  journal={The Astrophysical Journal},
We show that numerical simulations of reionization that resolve the Lyman limit systems (and, thus, correctly count absorptions of ionizing photons) have converged to about a 10% level for 5 < z < 6.2 and are in reasonable agreement (within 10%) with the SDSS data in this redshift interval. The SDSS data thus constrain the redshift of overlap of cosmic H II regions to zOVL = 6.1 ± 0.15. At higher redshifts, the simulations are far from convergence on the mean Gunn-Peterson optical depth but… 

Figures and Tables from this paper

Cosmic Reionization on Computers. I. Design and Calibration of Simulations
Cosmic Reionization On Computers is a long-term program of numerical simulations of cosmic reionization. Its goal is to model fully self-consistently (albeit not necessarily from the first
Reionization bias in high‐redshift quasar near‐zones
Absorption spectra of high-redshift quasars exhibit an increasingly thick Lyα forest, suggesting that the fraction of neutral hydrogen in the intergalactic medium (IGM) is increasing towards z ∼6.
Gas clumping in self-consistent reionization models
We use a suite of cosmological hydrodynamic simulations including a self-consistent treatment for inhomogeneous reionization to study the impact of galactic outflows and photoionization heating on
Constraining the quasar contribution to the reionization of cosmic hydrogen
Absorption spectra of high-redshift quasars suggest that the reionization of cosmic hydrogen was complete near z ∼ 6. The dominant sources of ionizing photons responsible for this reionization are
Radiative Transfer Simulations of Cosmic Reionization. I. Methodology and Initial Results
We present a new hybrid code for large-volume, high-resolution simulations of cosmic reionization, which utilizes an N-body algorithm for dark matter, physically motivated prescriptions for baryons
We carry out a new suite of cosmological radiation hydrodynamic simulations that explores the relative impacts on reionization-epoch star formation of galactic outflows and photoionization heating
Simulations of galaxy formation with radiative transfer: hydrogen reionization and radiative feedback
We carry out hydrodynamical simulations of galaxy formation that simultaneously follow radiative transfer of hydrogen-ionizing photons, based on the optically thin variable Eddington tensor
Quasar H II Regions During Cosmic Reionization
Cosmic reionization progresses as HII regions form around sources of ionizing radiation. Their average size grows continuously until they percolate and complete reionization. We demonstrate how this
Cosmic histories of star formation and reionization: an analysis with a power-law approximation
With a simple power-law approximation of high-redshift (3.5) star formation history, i.e., *(z)[(1+z)/4.5]??, we investigate the reionization of intergalactic medium (IGM) and the consequent Thomson
Observational Constraints of Reionization History in the JWST Era
The epoch of reionization is a crucial phase of cosmic evolution, when the UV photons from the first generation of galaxies and quasars ionized the neutral hydrogen in the IGM, ending the cosmic dark


Reionization of the Inhomogeneous Universe
A model of the density distribution in the intergalactic medium (IGM), motivated by that found in numerical simulations, is used to demonstrate the effect of a clumpy IGM and discrete sources on the
A very extended reionization epoch
The recent observations of cross temperature-polarization power spectra of the cosmic microwave background (CMB) made by the Wilkinson Microwave Anisotropy Probe (WMAP) satellite are in better
Cosmological Reionization by Stellar Sources
I use cosmological simulations that incorporate a physically motivated approximation to three- dimensional radiative transfer that recovers correct asymptotic ionization front propagation speeds for
Implications of WMAP 3 Year Data for the Sources of Reionization
New results on the anisotropy of the cosmic microwave background (CMB) and its polarization based on the first 3 years of data from the Wilkinson Microwave Anisotropy Probe (WMAP) have revised the
Evolution of the ionizing background and the epoch of reionization from the spectra of z ∼ 6 quasars
We study the process of cosmic reionization and estimate the ionizing background in the intergalactic medium (IGM) using the Lyman series absorption in the spectra of the four quasars at 5.7 3) are
Photon Consumption in Minihalos during Cosmological Reionization
At the earliest epochs of structure formation in cold dark matter (CDM) cosmologies, the smallest nonlinear objects are the numerous small halos that condense with virial temperatures below ~104 K.
Evolution of Lyman-limit absorption systems over the redshift range 0.40 < Z < 4.69
We present the results of a study of 15 z > 4.2 QSOs that extend statistical studies of Lyman-limit absorption line systems [N(H I) ≥ 1.6 x 10^(17) cm^(- 2)] to the highest redshifts currently
On the Evolution of the Ionizing Emissivity of Galaxies and Quasars Required by the Hydrogen Reionization
The average rate of emission of ionizing radiation per unit volume (or emissivity) in the universe can be calculated as the ratio of the intensity of the ionizing background to the mean free path of
Lyman Break Galaxies at z>4 and the Evolution of the UV Luminosity Density at High Redshift
We present initial results of a survey for star-forming galaxies in the redshift range 3.8 z 4.5. This sample consists of a photometric catalog of 244 galaxies culled from a total solid angle of 0.23
Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z~6 Quasars II: A Sample of 19 Quasars
We study the evolution of the ionization state of the intergalactic medium (IGM) at the end of the reionization epoch using moderate resolution spectra of a sample of nineteen quasars at 5.74 5.7: