Ly$\alpha$ Leaks and Reionization

Abstract

Ly$\alpha$ absorption spectra of QSOs at redshifts $z\simeq 6$ show complete Gunn-Peterson absorption troughs (dark gaps) separated by tiny leaks. The dark gaps are from the intergalactic medium (IGM) where the density of neutral hydrogen are high enough to produce almost saturated absorptions, however, where the transmitted leaks come from is still unclear so far. We demonstrate that leaking can originate from the lowest density voids in the IGM as well as the ionized patches around ionizing sources using semi-analytical simulations. If leaks were produced in lowest density voids, the IGM might already be highly ionized, and the ionizing background should be almost uniform; in contrast, if leaks come from ionized patches, the neutral fraction of IGM would be still high, and the ionizing background is significantly inhomogeneous. Therefore, the origin of leaking is crucial to determining the epoch of inhomogeneous-to-uniform transition of the the ionizing photon background. We show that the origin could be studied with the statistical features of leaks. Actually, Ly$\alpha$ leaks can be well defined and described by the equivalent width $W$ and the full width of half area $W_{\mathrm{H}}$, both of which are less contaminated by instrumental resolution and noise. It is found that the distribution of $W$ and $W_{\mathrm{H}}$ of Ly$\alpha$ leaks are sensitive to the modeling of the ionizing background. We consider four representative reionization models. It is concluded that the leak statistics provides an effective tool to probe the evolutionary history of reionization at $z\simeq 5-6.5$. Similar statistics would also be applicable to the reionization of He II at $z\simeq 3$(Abridged)

11 pages including 10 figures, accepted for publication in MNRAS

References in corpus (44)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Cosmological parameter analysis including SDSS Ly-alpha forest and galaxy bias: constraints on the primordial spectrum of fluctuations, neutrino mass, and dark energy
• 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
• Reionization of the Inhomogeneous Universe
• The Lyman Alpha Forest in the Spectra of QSOs
• Towards a Precise Measurement of Matter Clustering: Lyman-alpha Forest Data at Redshifts 2-4
• The Opacity of the Lyman Alpha Forest and Implications for Omega_{baryon} and the Ionizing Background
• Reionization of the Intergalactic Medium and the Damping Wing of the Gunn-Peterson Trough
• Galaxies at z~6: The UV Luminosity Function and Luminosity Density from 506 UDF, UDF-Ps, and GOODS i-dropouts
• Evolution of Structure in the Intergalactic Medium and the Nature of the Ly-alpha Forest
• Taxing the Rich: Recombinations and Bubble Growth During Reionization
• Simulating Cosmic Reionization at Large Scales II: the 21-cm Emission Features and Statistical Signals
• The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4
• Cosmic Reionisation by Stellar Sources: Population II Stars
• The Detectability of High Redshift Lyman Alpha Emission Lines Prior to the Reionization of the Universe
• Simulating IGM Reionization
• Experimental Constraints on Self-consistent Reionization Models
• A Study of the Reionization History of Intergalactic Helium with FUSE and VLT
• Approaching Reionization: The Evolution of the Lyman Alpha Forest from Redshifts Four to Six
• The Mass-To-Light Function: Antibias and Omega_m
• Cosmological Hydrogen Reionization with Three Dimensional Radiative Transfer
• Glimpsing through the high redshift neutral hydrogen fog
• The Lyman-alpha forest and WMAP year three
• Constraining the reionization history with QSO absorption spectra
• Probing the Intergalactic Medium with the Lyman alpha forest along multiple lines of sight to distant QSOs
• Reionization, SLOAN, and WMAP: is the Picture Consistent?
• How Universal is the Gunn-Peterson Trough at z~6?: A Closer Look at the Quasar SDSS J1148+5251
• Have We Detected Patchy Reionization in Quasar Spectra?
• Undetected Sources Allow Transmission of the Lyman-alpha Line From Galaxies Prior to Reionization
• Large-Scale Simulations of Reionization
• A Concordance Model of the Lyman-alpha Forest at z = 1.95
• 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
• A Statistical Analysis of Intergalactic Medium Transmission Approaching Reionization
• Temperature and Entropy Fields of Baryonic Gas in the Universe
• Low-Redshift Cosmic Baryon Fluid on Large Scales and She-Leveque Universal Scaling
• Measuring the galaxy power spectrum with multiresolution decomposition -- III. velocity field analysis
• Non-Gaussian Features of Transmitted Flux of QSO's Ly$\alpha$ Absorption: Intermittent Exponent
• Hydrogen Clouds before Reionization: a Lognormal Model Approach
• Non-Gaussianity of the Cosmic Baryon Fluid: Log-Poisson Hierarchy Model
• Is the cosmic UV background fluctuating at redshift z ~ 6 ?

Cited by in corpus (3)

• The Inhomogeneous Ionizing Background Following Reionization
• Log-Poisson Non-Gaussianity of Ly$\alpha$ Transmitted Flux Fluctuations at High Redshift
• Time-Dependent Behavior of Lyman$\alpha$ Photon Transfer in High Redshift Optically Thick Medium