Predictions for the clustering properties of the Lyman-alpha Forest - I. One-point statistics

Abstract

We present predictions for the one-point probability distribution and cumulants of the transmitted QSO flux in the high redshift Lyman-$\alpha$ Forest. We make use of the correlation between the Lyman-$\alpha$ optical depth and the underlying matter density predicted by gravitational instability theory and seen in numerical hydrodynamic simulations. We have modelled the growth of matter fluctuations using the non-linear shear-free dynamics, an approximation which reproduces well the results of perturbation theory for the cumulants in the linear and weakly non-linear clustering regime. As high matter overdensities tend to saturate in spectra, the statistics of the flux distribution are dominated by weakly non-linear overdensities. As a result, our analytic approach can produce accurate predictions, when tested against N-body simulation results, even when the underlying matter field has rms fluctuations larger than unity. Our treatment can be applied to either Gaussian or non-Gaussian initial conditions. Here we concentrate on the former case, but also include a study of a specific non-Gaussian model. We discuss how the methods and predictions we present can be used as a tool to study the generic clustering properties of the \lya forest at high-redshift. With such an approach, rather than concentrating on simulating specific cosmological models, we may be in the position to directly test our assumptions for the Gaussian nature of the initial conditions, and the gravitational instability origin of structure itself. In a separate paper we present results for two-point statistics.

New figures showing additional comparison with different simulation outputs. Matches published version

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Cited by in corpus (29)

• Towards a Precise Measurement of Matter Clustering: Lyman-alpha Forest Data at Redshifts 2-4
• The Evolution of Optical Depth in the Ly-alpha Forest: Evidence Against Reionization at z~6
• The one-dimensional Ly-alpha forest power spectrum from BOSS
• Probability Distribution Function of Cosmological Density Fluctuations from Gaussian Initial Condition: Comparison of One- and Two-point Log-normal Model Predictions with N-body Simulations
• 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
• Ionizing radiation fluctuations and large-scale structure in the Lyman-alpha forest
• A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth
• New approach for precise computation of Lyman-alpha forest power spectrum with hydrodynamical simulations
• Non-Linear gravitational growth of large scale structures inside and outside standard Cosmology
• Pressure Support vs. Thermal Broadening in the Lyman-alpha Forest I: Effects of the Equation of State on Longitudinal Structure
• The growth of structure in the intergalactic medium
• Inferring the Linear Power Spectrum from the Lyman-alpha Forest
• Tightening Constraints from the Lyman Alpha Forest with the Flux Probability Distribution Function
• On Estimating the QSO Transmission Power Spectrum
• Gravitational Evolution of the Large-Scale Probability Density Distribution: The Edgeworth & Gamma Expansions
• Perturbation theory and excursion set estimates of the probability distribution function of dark matter, and a method for reconstructing the initial distribution function
• The amplitude of mass density fluctuations at $z\approx 3.25$ from the Ly-alpha forest of Q1422+231
• The Probability Distribution of the Lya transmitted flux from a sample of SDSS quasars
• A Statistical Analysis of Intergalactic Medium Transmission Approaching Reionization
• Correlations in the Lyman alpha forest: testing the gravitational instability paradigm
• Divergence of Perturbation Theory in Large Scale Structures
• The Real and Redshift Space Density Distribution Function for Large-Scale Structure in the Spherical Collapse Approximation
• The nonlinear probability distribution function in models with local primordial non-Gaussianity
• The Lyman-alpha forest at redshifts 0.1 -- 1.6: good agreement between a large hydrodynamic simulation and HST spectra
• 2-Point Moments in Cosmological Large Scale Structure: I. Theory and Comparison with Simulations
• Ellipsoidal collapse and the redshift space probability distribution function of dark matter
• One-point Statistics of the Cosmic Density Field in Real and Redshift Spaces with A Multiresolutional Decomposition
• Lognormal semi-numerical simulations of the Lyman-$\alpha$ forest: comparison with full hydrodynamic simulations