The imprint of inhomogeneous HeII reionization on the HI and HeII Ly-alpha forest

Abstract

We use a set of AMR hydrodynamic simulations post-processed with the radiative-transfer code RADAMESH to study how inhomogeneous HeII reionization affects the intergalactic medium (IGM). We propagate radiation from active galactic nuclei (AGNs) considering two scenarios for the time evolution of the ionizing sources. We find that HeII reionization takes place in a very inhomogeneous fashion, through the production of well separated bubbles of the ionized phase that subsequently percolate. Overall, the reionization process is extended in time and lasts for a redshift interval Delta z>1. At fixed gas density, the temperature distribution is bimodal during the early phases of HeII reionization and cannot be described by a simple effective equation of state. When HeII reionization is complete, the IGM is characterized by a polytropic equation of state with index gamma~1.20. This relation is appreciably flatter than at the onset of the reionization process (gamma=1.56) and also presents a much wider dispersion around the mean. We extract HI and HeII Ly-alpha absorption spectra from the simulations and fit Voigt profiles to them. We find that the regions where helium is doubly ionized are characterized by different probability density functions of the curvature and of the Doppler b parameters of the HI Ly-alpha forest as a consequence of the bimodal temperature distribution during the early phases of HeII reionization. The column-density ratio in HeII and HI shows a strong spatial variability. Its probability density function rapidly evolves with time reflecting the increasing volume fraction in which ionizing radiation is harder due to the AGN contribution. Finally we show that the number density of the flux-transmission windows per unit redshift and the mean size of the dark gaps in the HeII spectra have the potential to distinguish between different reionization scenarios. (abridged)

arXiv comment24 pages, 30 figures. Matches version accepted for publication in MNRAS

References in corpus (64)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Cosmological Hydrodynamics with Adaptive Mesh Refinement: a new high resolution code called RAMSES
• Composite Quasar Spectra From the Sloan Digital Sky Survey
• Mass function of dark matter halos
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Sky Maps, Systematic Errors, and Basic Results
• Observational constraints on Cosmic Reionization
• Equation of State of the Photoionized Intergalactic Medium
• The Rest-Frame Extreme Ultraviolet Spectral Properties of QSOs
• The Lyman Alpha Forest in the Spectra of QSOs
• HOP: A New Group-Finding Algorithm for N-body Simulations
• The Lyman-alpha Forest Power Spectrum from the Sloan Digital Sky Survey
• Towards a Precise Measurement of Matter Clustering: Lyman-alpha Forest Data at Redshifts 2-4
• The thermal history of the intergalactic medium
• Clustering of High Redshift ($z\ge 2.9$) Quasars from the Sloan Digital Sky Survey
• The Linear Theory Power Spectrum from the Lyman-alpha Forest in the Sloan Digital Sky Survey
• Multiscale Gaussian Random Fields for Cosmological Simulations
• The Physics of the Intergalactic Medium
• Detection of Extended He II Reionization in the Temperature Evolution of the Intergalactic Medium
• Quasar Clustering and the Lifetime of Quasars
• HeII Reionization and its Effect on the IGM
• The Evolution of the Effective Equation of State of the IGM
• A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2
• Cosmic Evolution of Quasar Clustering: Implications for the Host Haloes
• A Refined Measurement of the Mean Transmitted Flux in the Ly-alpha Forest over 2 < z < 5 Using Composite Quasar Spectra
• Constraining the Lifetime of Quasars from their Spatial Clustering
• A Measurement of the Temperature-Density Relation in the Intergalactic Medium Using a New Lyman-alpha Absorption Line Fitting Method
• Cosmic Reionisation by Stellar Sources: Population II Stars
• A Measurement of Small Scale Structure in the 2.2 < z < 4.2 Lyman-alpha Forest
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• Constraints from the Lyman alpha forest power spectrum
• A Physical Model for the Luminosity Function of High-Redshift Quasars
• An improved measurement of the flux distribution of the Ly-alpha forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties
• The Faint End of the Quasar Luminosity Function at z~4: Implications for Ionization of the Intergalactic Medium and Cosmic Downsizing
• A Study of the Reionization History of Intergalactic Helium with FUSE and VLT
• Caught in the act: a helium-reionizing quasar near the line of sight to Q0302-003
• An unbiased measurement of the UV background and its evolution via the proximity effect in quasar spectra
• The End of Helium Reionization at z~2.7 Inferred from Cosmic Variance in HST/COS HeII Lyman Alpha Absorption Spectra
• The Temperature-Density Relation in the Intergalactic Medium at Redshift <z>=2.4
• Cosmological and astrophysical constraints from the Lyman-alpha forest flux probability distribution function
• Resolving the Helium Lyman-$\alpha$ Forest: Mapping Intergalactic Gas and Ionizing Radiation at $z\approx 3$
• A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth
• The most luminous quasars do not live in the most massive dark matter haloes at any redshift
• The intergalactic medium thermal history at redshift z=1.7--3.2 from the Lyman alpha forest: a comparison of measurements using wavelets and the flux distribution
• The Epoch of Helium Reionization
• The b Distribution of the Lya Forest: Probing Cosmology and the Intergalactic Medium
• GALEX far-UV color selection of UV-bright high-redshift quasars
• Detection of He II reionization in the SDSS quasar sample
• The UV spectrum of HS1700+6416 II. FUSE observations of the HeII Lyman alpha forest
• Reionisation scenarios and the temperature of the IGM
• Photo-heating and the fate of hard photons during the reionisation of HeII by quasars
• The Lyman alpha forest flux probability distribution at z>3
• Intergalactic HeII absorption towards QSO 1157+3143
• RADAMESH: Cosmological Radiative Transfer for Adaptive Mesh Refinement Simulations
• Plausible fluorescent Ly-alpha emitters around the z=3.1 QSO0420-388
• The impact of helium reionization on the structure of the intergalactic medium
• The Structure and Evolution of Lyman-alpha Forest Clouds in the Minihalo Model
• HST/COS Observations of Thirteen New He II Quasars
• A High Yield of New Sightlines for the Study of Intergalactic Helium: Far-UV-Bright Quasars from SDSS, GALEX, and HST
• The evolution of the Lyman-alpha forest effective optical depth following HeII reionisation
• Ten More New Sightlines for the Study of Intergalactic Helium, and Hundreds of Far-UV-Bright Quasars, from SDSS, GALEX, and HST
• Late Reheating of the IGM by Quasars: A Radiation Hydrodynamical Simulation of Helium II Reionization
• The UV background photoionization rate at 2.3 < z < 4.6 as measured from the Sloan Digital Sky Survey

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