Is the cosmic UV background fluctuating at redshift z ~ 6 ?

Abstract

We study the Gunn-Peterson effect of the photo-ionized intergalactic medium(IGM) in the redshift range 5< z <6.4 using semi-analytic simulations based on the lognormal model. Assuming a rapidly evolved and spatially uniform ionizing background, the simulation can produce all the observed abnormal statistical features near redshift z ~ 6. They include: 1) rapidly increase of absorption depths; 2) large scatter in the optical depths; 3) long-tailed distributions of transmitted flux and 4) long dark gaps in spectra. These abnormal features are mainly due to rare events, which correspond to the long-tailed probability distribution of the IGM density field, and therefore, they may not imply significantly spatial fluctuations in the UV ionizing background at z ~ 6.

12 pages, 4 figs, accepted by ApJL

References in corpus (32)

• Equation of State of the Photoionized Intergalactic Medium
• Evolution of the Ionizing Background and the Epoch of Reionization from the Spectra of z~6 Quasars
• The Lyman Alpha Forest in the Spectra of QSOs
• Luminosity functions of Lyman-alpha emitters at z=6.5, and z=5.7: evidence against reionization at z=6
• Evolution of Structure in the Intergalactic Medium and the Nature of the Ly-alpha Forest
• Probing the Ionization State of the Universe at z>6
• The Evolution of the Intergalactic Medium Transmission to Redshift Six
• Evolution of One-Point Distributions from Gaussian Initial Fluctuations
• Approaching Reionization: The Evolution of the Lyman Alpha Forest from Redshifts Four to Six
• Cosmological Hydrogen Reionization with Three Dimensional Radiative Transfer
• Discovery of excess O I absorption towards the z = 6.42 QSO SDSS J1148+5251
• Reionization, SLOAN, and WMAP: is the Picture Consistent?
• A first step towards a direct inversion of the Lyman forest in QSO spectra
• Have We Detected Patchy Reionization in Quasar Spectra?
• Undetected Sources Allow Transmission of the Lyman-alpha Line From Galaxies Prior to Reionization
• The growth of structure in the intergalactic medium
• Semi analytic approach to understanding the distribution of neutral hydrogen in the universe: Comparison of simulations with observations
• A Simulation of Ly-alpha Absorption Forests in Linear Approximation in Cold and Cold+Hot Dark Matter Models
• Stochastic fluctuations and structure formation in the Universe
• Non-Gaussianity and the recovery of the mass power spectrum from the Ly$\alpha$ forest
• A Statistical Analysis of Intergalactic Medium Transmission Approaching Reionization
• Temperature and Entropy Fields of Baryonic Gas in the Universe
• Measuring the galaxy power spectrum with multiresolution decomposition -- III. velocity field analysis
• Intermittent Features of the QSO Ly$\alpha$ Transmitted Flux: Results from Hydrodynamic Cosmological Simulations
• Intermittent behavior of cosmic mass field revealed by QSO's Ly_alpha forests
• Multiple-streaming and the Probability Distribution of Density in Redshift Space
• Non-Gaussian Features of Transmitted Flux of QSO's Ly$\alpha$ Absorption: Intermittent Exponent
• Power spectrum and intermittency of the transmitted flux of QSOs Ly-alpha absorption spectra
• The intermittent behavior and hierarchical clustering of the cosmic mass field
• Hydrogen Clouds before Reionization: a Lognormal Model Approach
• The local power spectrum and correlation hierarchy of the cosmic mass field
• Power Spectrum and Intermittency of Ly$\alpha$ Transmitted Flux of QSO He2347-4342

Cited by in corpus (9)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Studying Reionization with Ly-alpha Emitters
• The Evolution of Optical Depth in the Ly-alpha Forest: Evidence Against Reionization at z~6
• The nature and evolution of the highly ionized near-zones in the absorption spectra of z~6 quasars
• Quasar Proximity Zones and Patchy Reionization
• Glimpsing through the high redshift neutral hydrogen fog
• Log-Poisson Non-Gaussianity of Ly$\alpha$ Transmitted Flux Fluctuations at High Redshift
• Ly$\alpha$ Leaks in the Absorption Spectra of High Redshift QSOs
• Ly$\alpha$ Leaks and Reionization