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We present a suite of cosmological N-body simulations with cold dark matter and baryons aiming at modeling the low-density regions of the IGM as probed by the Lyman-$\alpha$ forests at high redshift. The simulations are designed to match…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 A. Borde , N. Palanque-Delabrouille , G. Rossi , M. Viel , J. Bolton , Ch. Yèche , J. -M. LeGoff , J. Rich

Observations of the Lyman-$\alpha$ forest in distant quasar spectra with upcoming surveys are expected to provide significantly larger and higher-quality datasets. To interpret these datasets, it is imperative to develop efficient…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-13 Bhaskar Arya , Tirthankar Roy Choudhury , Aseem Paranjape , Prakash Gaikwad

We test a method to reduce unwanted sample variance when predicting Lyman-$\alpha$ (ly$\alpha$) forest power spectra from cosmological hydrodynamical simulations. Sample variance arises due to sparse sampling of modes on large scales and…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-16 Lauren Anderson , Andrew Pontzen , Andreu Font-Ribera , Francisco Villaescusa-Navarro , Keir K. Rogers , Shy Genel

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

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

Upcoming 21cm surveys will map the spatial distribution of cosmic neutral hydrogen (HI) over very large cosmological volumes. In order to maximize the scientific return of these surveys, accurate theoretical predictions are needed.…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-29 Digvijay Wadekar , Francisco Villaescusa-Navarro , Shirley Ho , Laurence Perreault-Levasseur

In this work, we analyze the Lyman-$\alpha$ forest in cosmological hydrodynamical simulations of chameleon-type f(R) gravity with the goal to assess whether the impact of such models is detectable in absorption line statistics. We carry out…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Christian Arnold , Ewald Puchwein , Volker Springel

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…

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 describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body…

Astrophysics · Physics 2008-02-03 David H. Weinberg , Neal Katz , Lars Hernquist

We present a neural network emulator to constrain the thermal parameters of the intergalactic medium (IGM) at $\displaystyle{5.4}\le{z}\le{6.0}$ using the Lyman-$\displaystyle\alpha$ (Ly$\displaystyle\alpha$) forest flux auto-correlation…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-24 Zhenyu Jin , Molly Wolfson , Joseph F. Hennawi , Diego González-Hernández

We analyze the flux power spectrum and its covariance using simulated Lyman alpha forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques…

Astrophysics · Physics 2009-11-11 Hu Zhan , Romeel Dave , Daniel Eisenstein , Neal Katz

The filamentary network of intergalactic medium (IGM) gas that gives origin to the Lyman-alpha forest in the spectra of distant quasars encodes information on the physics of structure formation and the early thermodynamics of diffuse…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Bruno Villasenor , Brant Robertson , Piero Madau , Evan Schneider

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

We present a general framework for obtaining robust bounds on the nature of dark matter using cosmological $N$-body simulations and Lyman-alpha forest data. We construct an emulator of hydrodynamical simulations, which is a flexible,…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-23 Keir K. Rogers , Hiranya V. Peiris

We present the Lyssa suite of high-resolution cosmological simulations of the Lyman-$\alpha$ forest designed for cosmological analyses. These 18 simulations have been run using the Nyx code with $4096^3$ hydrodynamical cells in a 120 Mpc…

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 present a neural-network emulator for baryonic effects in the non-linear matter power spectrum. We calibrate this emulator using more than 50,000 measurements in a 15-dimensional parameters space, varying cosmology and baryonic physics.…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-11 Giovanni Aricò , Raul E. Angulo , Sergio Contreras , Lurdes Ondaro-Mallea , Marcos Pellejero-Ibañez , Matteo Zennaro

We introduce a new set of large scale, high resolution hydrodynamical simulations of the intergalactic medium: the Sherwood simulation suite. These are performed in volumes 10^3-160^3 h^-3 comoving Mpc^{3}, span almost four orders of…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-07 James S. Bolton , Ewald Puchwein , Debora Sijacki , Martin G. Haehnelt , Tae-Sun Kim , Avery Meiksin , John A. Regan , Matteo Viel

Measurements of the Ly$\alpha$ forest based on large numbers of quasar spectra from sky surveys such as SDSS/eBOSS accurately probe the distribution of matter on small scales and thus provide important constraints on several ingredients of…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-22 Michael Walther , Eric Armengaud , Corentin Ravoux , Nathalie Palanque-Delabrouille , Christophe Yèche , Zarija Lukić