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We present LyMAS2, an improved version of the "Lyman-{\alpha} Mass Association Scheme" aiming at predicting the large-scale 3d clustering statistics of the Lyman-{\alpha} forest (Ly-{\alpha}) from moderate resolution simulations of the dark…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 S. Peirani , S. Prunet , S. Colombi , C. Pichon , D. H. Weinberg , C. Laigle , G. Lavaux , Y. Dubois , J. Devriendt

We develop a machine learning based algorithm using a convolutional neural network (CNN) to identify low HI column density Ly$\alpha$ absorption systems ($\log{N_{\mathrm{HI}}}/{\rm cm}^{-2}<17$) in the Ly$\alpha$ forest, and predict their…

Astrophysics of Galaxies · Physics 2022-09-28 Ting-Yun Cheng , Ryan Cooke , Gwen Rudie

This study sets new constraints on Cold+Warm Dark Matter (CWDM) models by leveraging the small-scale suppression of structure formation imprinted in the Lyman-$\alpha$ forest. Using the Sherwood-Relics suite, we extract high-fidelity flux…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Olga Garcia-Gallego , Vid Iršič , Martin G. Haehnelt , Matteo Viel , James S. Bolton

The standard cosmological analysis with the Ly$\alpha$ forest relies on a continuum fitting procedure that suppresses information on large scales and distorts the three-dimensional correlation function on all scales. In this work, we…

[abridged] We describe LyMAS (Ly-alpha Mass Association Scheme), a method of predicting clustering statistics in the Ly-alpha forest on large scales from moderate resolution simulations of the dark matter distribution, with calibration from…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-05 Sébastien Peirani , David H. Weinberg , Stéphane Colombi , Jérémy Blaizot , Yohan Dubois , Christophe Pichon

We present zELDA(redshift Estimator for Line profiles of Distant Lyman-Alpha emitters), an open source code to fit Lyman-Alpha (Lya) line profiles. The main motivation is to provide the community with an easy to use and fast tool to analyze…

Astrophysics of Galaxies · Physics 2021-12-22 Siddhartha Gurung-Lopez , Max Gronke , Shun Saito , Silvia Bonoli , Alvaro A. Orsi

Compressing large data sets to a manageable number of summaries that are informative about the underlying parameters vastly simplifies both frequentist and Bayesian inference. When only simulations are available, these summaries are…

Instrumentation and Methods for Astrophysics · Physics 2018-08-06 Tom Charnock , Guilhem Lavaux , Benjamin D. Wandelt

The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light…

The Lyman-$\alpha$ forest is a valuable probe of dark matter models featuring a scale-dependent suppression of the power spectrum as compared to $\Lambda$CDM. In this work, we present a new estimator of the Lyman-$\alpha$ flux power…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Mathias Garny , Thomas Konstandin , Laura Sagunski , Sean Tulin

We address the problem of inferring the three-dimensional matter distribution from a sparse set of one-dimensional quasar absorption spectra of the Lyman-$\alpha$ forest. Using a Bayesian forward modelling approach, we focus on extending…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Natalia Porqueres , Oliver Hahn , Jens Jasche , Guilhem Lavaux

Cosmological simulations with gas provide a detailed description of the intergalactic medium, making possible predictions of neutral hydrogen absorption in the spectra of background QSOs. We present results from a high-resolution…

Astrophysics · Physics 2009-10-28 Lars Hernquist , Neal Katz , David H. Weinberg , Jordi Miralda-Escude

We study the statistics of the Lyman-$\alpha$ forest in a flat LCDM cosmology with the N-body + Eulerian hydrodynamics code Nyx. We produce a suite of simulations, covering the observationally relevant redshift range $2 \leq z \leq 4$. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-24 Zarija Lukić , Casey Stark , Peter Nugent , Martin White , Avery Meiksin , Ann Almgren

We analyze the SDSS Ly-alpha forest P_F(k,z) measurement to determine the linear theory power spectrum. Our analysis is based on fully hydrodynamic simulations, extended using hydro-PM simulations. We account for the effect of absorbers…

We present a novel maximum a posteriori estimator to jointly estimate band-powers and the covariance of the three-dimensional power spectrum (P3D) of Lyman-alpha forest flux fluctuations, called MAPLE. Our Wiener-filter based algorithm…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-27 Benjamin Horowitz , Roger de Belsunce , Zarija Lukic

We present 40 fully hydrodynamical numerical simulations of the intergalactic gas that gives rise to the Ly-alpha forest. We make artificial spectra from each and measure three output parameters: the mean flux, a measure of the most common…

Current analyses of the Lyman-alpha forest assume that the primordial power spectrum of density perturbations obeys a simple power law, a strong theoretical assumption which should be tested. Employing a large suite of numerical simulations…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-24 Simeon Bird

(abridged) The flux power spectrum of the Lyman-alpha forest in quasar (QSO) absorption spectra is sensitive to a wide range of cosmological and astrophysical parameters and instrumental effects. Modelling the flux power spectrum in this…

Astrophysics · Physics 2015-06-24 Matteo Viel , Martin G. Haehnelt

Recent studies have focused on the low-$z$ Ly$\alpha$ forest as a potential constraint on galactic feedback, as different AGN and stellar feedback models in hydrodynamic simulations produce varying intergalactic medium (IGM) statistics.…

Astrophysics of Galaxies · Physics 2025-08-26 Megan T. Tillman , Joseph N. Burchett , Blakesley Burkhart , Vikram Khaire , Sanchayeeta Borthakur

We use hydrodynamic simulations to predict correlations between Lya forest absorption and galaxies at redshift z~3. The probability distribution function (PDF) of Lya flux decrements shifts systematically towards higher values in the…

Astrophysics · Physics 2009-11-07 Juna A. Kollmeier , David H. Weinberg , Romeel Dave' , Neal Katz