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Related papers: Fast, high-fidelity Lyman $\alpha$ forests with co…

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A convincing physical picture for the Lyman-alpha forest has emerged from simulations and related semi-analytic studies of structure formation models. Observations can be be used in the context of this picture to study cosmology using the…

Astrophysics · Physics 2007-05-23 Rupert Croft , David Weinberg , Neal Katz , Lars Hernquist

We explore several physical effects on the power spectrum of the Lyman-alpha forest transmitted flux. The effects we investigate here are usually not part of hydrodynamic simulations and so need to be estimated separately. The most…

Astrophysics · Physics 2009-11-10 P. McDonald , U. Seljak , R. Cen , P. Bode , J. P. Ostriker

The Ly$\alpha$ forest, a series of HI absorption lines in the quasar spectra, is a powerful tool for probing the large-scale structure of the intergalactic medium. Its three-dimensional (3D) correlation and cross-correlations with quasars…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-23 Koichiro Nakashima , Atsushi J. Nishizawa , Kentaro Nagamine , Yuri Oku , Ikkoh Shimizu

When performing cosmological inference, standard analyses of the Lyman-$\alpha$ (Ly$\alpha$) three-dimensional correlation functions only consider the information carried by the distinct peak produced by baryon acoustic oscillations (BAO).…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-14 Francesca Gerardi , Andrei Cuceu , Andreu Font-Ribera , Benjamin Joachimi , Pablo Lemos

We present an effective field theory (EFT) approach to extract fundamental cosmological parameters from the Lyman-alpha forest flux fluctuations as an alternative to the standard simulation-based techniques. As a first application, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-21 Mikhail M. Ivanov , Michael W. Toomey , Naim Göksel Karaçaylı

Interpreting observations of the Lyman-$\alpha$ forest flux power spectrum requires interpolation between a small number of expensive simulations. We present a Gaussian process emulator modelling the 1D flux power spectrum as a function of…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-17 Christian Pedersen , Andreu Font-Ribera , Keir K. Rogers , Patrick McDonald , Hiranya V. Peiris , Andrew Pontzen , Anže Slosar

The quest for the neutrino mass is a central goal in contemporary cosmology, subject to intense scrutiny, and among different large-scale structure tracers the Lyman-Alpha forest is re-emerging as a unique tool to probe the neutrino mass at…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-23 Graziano Rossi

As the climate changes, the severity of wildland fires is expected to worsen. Models that accurately capture fire propagation dynamics greatly help efforts for understanding, responding to and mitigating the damages caused by these fires.…

Machine Learning · Computer Science 2021-04-12 John Burge , Matthew Bonanni , Matthias Ihme , Lily Hu

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 use LUQAS, a sample of 27 high resolution high signal-to-noise UVES quasar (QSO) spectra (Kim et al. 2004), and the Croft et al. (2002) sample together with a set of high resolution large box size hydro-dynamical simulations run with the…

Astrophysics · Physics 2009-11-11 Matteo Viel

We study and compare fitting methods for the Lyman-$\alpha$ (Ly$\alpha$) forest 3D correlation function. We use the nested sampler PolyChord and the community code picca to perform a Bayesian analysis which we compare with previous…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Andrei Cuceu , Andreu Font-Ribera , Benjamin Joachimi

We build a field level emulator for cosmic structure formation that is accurate in the nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-02 Drew Jamieson , Yin Li , Renan Alves de Oliveira , Francisco Villaescusa-Navarro , Shirley Ho , David N. Spergel

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 present a novel Bayesian method for the joint reconstruction of cosmological matter density fields, peculiar velocities and power-spectra in the quasi-nonlinear regime. We study its applicability to the Ly-alpha forest based on multiple…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Francisco-Shu Kitaura , Simona Gallerani , Andrea Ferrara

We develop an analytical method based on the lognormal approximation to compute the column density distribution of the Lyman-alpha forest in the low column density limit. We compute the column density distributions for six different…

Astrophysics · Physics 2009-10-28 Nickolay Y. Gnedin , Lam Hui

We develop a new and simple method to model baryonic effects at the field level relevant for weak lensing analyses. We analyze thousands of state-of-the-art hydrodynamic simulations from the CAMELS project, each with different cosmology and…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-01 Divij Sharma , Biwei Dai , Francisco Villaescusa-Navarro , Uros Seljak

We present Neural Random Forest Imitation - a novel approach for transforming random forests into neural networks. Existing methods propose a direct mapping and produce very inefficient architectures. In this work, we introduce an imitation…

Machine Learning · Computer Science 2024-04-05 Christoph Reinders , Bodo Rosenhahn

We describe techniques for comparing spectra extracted from cosmological simulations and observational data, using the same methodology to link Lyman-alpha properties derived from the simulations with properties derived from observational…

Astrophysics · Physics 2009-11-07 C. E. Petry , C. D. Impey , N. Katz , D. H. Weinberg , L. E. Hernquist

We have performed high-resolution hydrodynamic simulations of the Lyman-alpha forest in a variety of popular cold dark matter dominated cosmologies, including a low density and a vacuum-dominated model. The fluctuation amplitude of these…

Astrophysics · Physics 2009-10-31 Tom Theuns , Anthony Leonard , Joop Schaye , George Efstathiou

We present a same-level comparison of the most prominent inversion methods for the reconstruction of the matter density field in the quasi-linear regime from the Ly$\alpha$ forest flux. Moreover, we present a pathway for refining the…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 Hendrik Müller , Christoph Behrens , David James Edward Marsh
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