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Related papers: Ly$\alpha$NNA: A Deep Learning Field-level Inferen…

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Deep learning (DL) has been shown to outperform traditional, human-defined summary statistics of the Ly{\alpha} forest in constraining key astrophysical and cosmological parameters owing to its ability to tap into the realm of non-Gaussian…

Instrumentation and Methods for Astrophysics · Physics 2025-10-24 Parth Nayak , Michael Walther , Daniel Gruen

We explore the use of Deep Learning to infer physical quantities from the observable transmitted flux in the Lyman-alpha forest. We train a Neural Network using redshift z=3 outputs from cosmological hydrodynamic simulations and mock…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-07 Lawrence Huang , Rupert A. C. Croft , Hitesh Arora

The Lyman-$\alpha$ forest offers a unique avenue for studying the distribution of matter in the high redshift universe and extracting precise constraints on the nature of dark matter, neutrino masses, and other $\Lambda$CDM extensions.…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-29 Laura Cabayol-Garcia , Jonás Chaves-Montero , Andreu Font-Ribera , Christian Pedersen

We perform for the first time full simulation-based inference on the Lyman-$\alpha$ forest 1D power spectrum. In particular, we consider the prediction of the Lyman-$\alpha$ forest $P_{\rm 1D}(k)$ at $2.0<z<3.5$ from the CAMELS cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-26 Francesco Sinigaglia , Patricia Iglesias-Navarro , Matteo Viel

The inference of cosmological quantities requires accurate and large hydrodynamical cosmological simulations. Unfortunately, their computational time can take millions of CPU hours for a modest coverage in cosmological scales ($\approx (100…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-03 Chotipan Boonkongkird , Guilhem Lavaux , Sebastien Peirani , Yohan Dubois , Natalia Porqueres , Eleni Tsaprazi

The Lyman-$\alpha$ forest refers to the series of absorption features observed in the spectra of distant quasars that are produced by neutral hydrogen in the intergalactic medium. Observed over a wide range of redshifts with both ground-…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-22 Jonás Chaves-Montero

We aim to present a robust parameter estimation with simulated Lya forest spectra from Sherwood-Relics simulations suite using Information Maximizing Neural Network(IMNN) to extract maximal information from Lya 1D-transmitted flux in…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-09 Soumak Maitra , Stefano Cristiani , Matteo Viel , Roberto Trotta , Guido Cupani

Full-physics cosmological simulations are powerful tools for studying the formation and evolution of structure in the universe but require extreme computational resources. Here, we train a convolutional neural network to use a cheaper…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-04 Peter Harrington , Mustafa Mustafa , Max Dornfest , Benjamin Horowitz , Zarija Lukić

Lyman-$\alpha$(Ly$\alpha$) forest in the spectra of distant quasars encodes the information of the underlying cosmic density field at smallest scales. The modelling of the upcoming large and high-fidelity forest data using cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-10 Bhaskar Arya

Unveiling the thermal history of the intergalactic medium (IGM) at $4 \leq z \leq 5$ holds the potential to reveal early onset HeII reionization or lingering thermal fluctuations from HI reionization. We set out to reconstruct the IGM gas…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-10 Fahad Nasir , Prakash Gaikwad , Frederick B. Davies , James S. Bolton , Ewald Puchwein , Sarah E. I. Bosman

We aim to construct a machine-learning approach that allows for a pixel-by-pixel reconstruction of the intergalactic medium (IGM) density field for various warm dark matter (WDM) models using the Lyman-alpha forest. With this regression…

The distribution of absorption lines in the spectra of distant quasars, called the Lyman-$\alpha$ (Ly-$\alpha$) forest, is a unique probe of cosmology and the intergalactic medium at high redshifts and small scales. The statistical power of…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Roger de Belsunce , Mikhail M. Ivanov , James M. Sullivan , Kazuyuki Akitsu , Shi-Fan Chen

Current results from the Lyman alpha forest assume that the primordial power spectrum of density perturbations follows a simple power law form, with running. We present the first analysis of Lyman alpha data to study the effect of relaxing…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-16 Simeon Bird , Hiranya V. Peiris , Matteo Viel , Licia Verde

The hyperfine structure absorption lines of neutral hydrogen in spectra of high-redshift radio sources, known collectively as the 21-cm forest, have been demonstrated as a sensitive probe to the small-scale structures governed by the dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Tian-Yang Sun , Yue Shao , Yichao Li , Yidong Xu , He Wang , Xin Zhang

We derive and numerically implement an algorithm for estimating the 3D power spectrum of the Lyman-$\alpha$ (Ly-$\alpha$) forest flux fluctuations. The algorithm exploits the unique geometry of Ly-$\alpha$ forest data to efficiently measure…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-10 Andreu Font-Ribera , Patrick McDonald , Anže Slosar

We explore the use of Deep Learning to infer the temperature of the intergalactic medium from the transmitted flux in the high redshift Lyman-alpha forest. We train Neural Networks on sets of simulated spectra from redshift z=2-3 outputs of…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-06 Runxuan Wang , Rupert A. C. Croft , Patrick Shaw

The forest of Lyman-$\alpha$ absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic material. Its main observable -- the 1D flux…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-19 Bruno Villasenor , Brant Robertson , Piero Madau , Evan Schneider

In order to compress and more easily interpret Lyman-$\alpha$ forest (Ly$\alpha$F) datasets, summary statistics, e.g. the power spectrum, are commonly used. However, such summaries unavoidably lose some information, weakening the…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-06 S. Chang , P. Nayak , M. Walther , D. Gruen

This work presents a new physically-motivated supervised machine learning method, Hydro-BAM, to reproduce the three-dimensional Lyman-$\alpha$ forest field in real and in redshift space learning from a reference hydrodynamic simulation,…

On large scales, the Lyman-$\alpha$ forest provides insights into the expansion history of the Universe, while on small scales, it imposes strict constraints on the growth history, the nature of dark matter, and the sum of neutrino masses.…

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