Modeling the Lyman-alpha Forest in Collisionless Simulations

Abstract

Cosmological hydrodynamic simulations can accurately predict the properties of the intergalactic medium (IGM), but only under the condition of retaining high spatial resolution necessary to resolve density fluctuations in the IGM. This resolution constraint prohibits simulating large volumes, such as those probed by BOSS and future surveys, like DESI and 4MOST. To overcome this limitation, we present Iteratively Matched Statistics (IMS), a novel method to accurately model the Lyman-alpha forest with collisionless N-body simulations, where the relevant density fluctuations are unresolved. We use a small-box, high-resolution hydrodynamic simulation to obtain the probability distribution function (PDF) and the power spectrum of the real-space Lyman-alpha forest flux. These two statistics are iteratively mapped onto a pseudo-flux field of an N-body simulation, which we construct from the matter density. We demonstrate that our method can perfectly reproduce line-of-sight observables, such as the PDF and power spectrum, and accurately reproduce the 3D flux power spectrum (5-20%). We quantify the performance of the commonly used Gaussian smoothing technique and show that it has significantly lower accuracy (20-80%), especially for N-body simulations with achievable mean inter-particle separations in large-volume simulations. In addition, we show that IMS produces reasonable and smooth spectra, making it a powerful tool for modeling the IGM in large cosmological volumes and for producing realistic "mock" skies for Lyman-alpha forest surveys.

25 pages, 15 figures, submitted to ApJ

References in corpus (5)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function
• The Acoustic Peak in the Lyman Alpha Forest

Cited by in corpus (25)

• LATIS: The Ly$\alpha$ Tomography IMACS Survey
• A New Precision Measurement of the Small-Scale Line-of-Sight Power Spectrum of the Ly$\alpha$ Forest
• TARDIS Paper I: A Constrained Reconstruction Approach to Modeling the z~2.5 Cosmic Web Probed by Lyman-alpha Forest Tomography
• Inferring high redshift large-scale structure dynamics from the Lyman-alpha forest
• Revealing the z~2.5 Cosmic Web With 3D Lyman-Alpha Forest Tomography: A Deformation Tensor Approach
• Simba: The average properties of the circumgalactic medium of $2\le z\le 3$ quasars are determined primarily by stellar feedback
• Probing Feedback via IGM tomography and Ly$\alpha$ forest with Subaru PFS, TMT/ELT, and JWST
• A Fundamental Test for Galaxy Formation Models: Matching the Lyman-$\alpha$ Absorption Profiles of Galactic Halos over Three Decades in Distance
• Characterizing Protoclusters and Protogroups at z $\sim$ 2.5 Using Ly$\alpha$ Tomography
• A hierarchical field-level inference approach to reconstruction from sparse Lyman-$\alpha$ forest data
• Dark acoustic oscillations: Imprints on the matter power spectrum and the halo mass function
• Efficient adiabatic hydrodynamical simulations of the high-redshift intergalactic medium
• Observational Evidence for Large-Scale Gas Heating in a Galaxy Protocluster at z=2.30
• Mapping Lyman-alpha forest three-dimensional large scale structure in real and redshift space
• A Novel Statistical Method for Measuring the Temperature-Density Relation in the IGM Using the $b$-$N_{\text{HI}}$ Distribution of Absorbers in the Ly$\alpha$ Forest
• Fast, high-fidelity Lyman $\alpha$ forests with convolutional neural networks
• Probing the environment of high-z quasars using the proximity effect in projected quasar pairs
• HyPhy: Deep Generative Conditional Posterior Mapping of Hydrodynamical Physics
• Planting a Lyman alpha forest on AbacusSummit
• Constraining the Fluctuating Gunn-Peterson Approximation Using Lyman-$\alpha$ Forest Tomography at $z=2$
• LyMAS reloaded: improving the predictions of the large-scale Lyman-α forest statistics from dark matter density and velocity fields
• Three- and two-point spatial correlations of IGM at $z\sim 2$: Cloud based analysis using simulations
• Lognormal semi-numerical simulations of the Lyman-$\alpha$ forest: comparison with full hydrodynamic simulations
• Modeling the Cosmological Lyman-$\alpha$ Forest at the Field Level
• Bridging Simulations and EFT: A Hybrid Model of the Lyman-Alpha Forest Field