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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 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…

We present methods for interpolating between the 1-D flux power spectrum of the Lyman-$\alpha$ forest, as output by cosmological hydrodynamic simulations. Interpolation is necessary for cosmological parameter estimation due to the limited…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-25 Simeon Bird , Keir K. Rogers , Hiranya V. Peiris , Licia Verde , Andreu Font-Ribera , Andrew Pontzen

Physics-informed neural networks have emerged as a coherent framework for building predictive models that combine statistical patterns with domain knowledge. The underlying notion is to enrich the optimization loss function with known…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-20 Zhenyu Dai , Ben Moews , Ricardo Vilalta , Romeel Dave

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

The Lyman-alpha forest provides strong constraints on both cosmological parameters and intergalactic medium astrophysics, which are forecast to improve further with the next generation of surveys including eBOSS and DESI. As is generic in…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-19 Keir K. Rogers , Hiranya V. Peiris , Andrew Pontzen , Simeon Bird , Licia Verde , Andreu Font-Ribera

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

The Ly$\alpha$ forest (LAF) at $z>5$ probes the thermal and reionization history of the intergalactic medium (IGM) and the nature of dark matter, but its interpretation requires comparison to cosmological hydrodynamical simulations. At…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-26 Caitlin C. Doughty , Joseph F. Hennawi , Frederick B. Davies , Zarija Lukić , Jose Oñorbe

[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

Our understanding of the Lyman-$\alpha$ forest has received a great boost with the advent of the Keck Telescope and large 3D hydrodynamical simulations. We present new simulations using the SPH technique with a P^3MG (Particle-Particle…

Astrophysics · Physics 2007-05-23 J. W. Wadsley , J. Richard Bond

We present the PRIYA suite of cosmological simulations, based on the code and hydrodynamic model of the ASTRID simulation, and designed for cosmological analyses of the Lyman-$\alpha$ forest. Our simulation suite spans a $9$-dimensional…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-04 Simeon Bird , Martin Fernandez , Ming-Feng Ho , Mahdi Qezlou , Reza Monadi , Yueying Ni , Nianyi Chen , Rupert Croft , Tiziana Di Matteo

We compare the low redshift (z ~ 0.1) Lyman-alpha forest from hydrodynamical simulations with data from the Cosmic Origin Spectrograph (COS). We find tension between the observed number of lines with b-parameters in the range 25-45 km/s and…

Astrophysics of Galaxies · Physics 2017-04-19 M. Viel , M. G. Haehnelt , J. S. Bolton , T. -S. Kim , E. Puchwein , F. Nasir , B. P. Wakker

Estimates of the metagalactic hydrogen ionization rate from the Lyman-alpha forest opacity in QSO absorption spectra depend on the complex density distribution of neutral hydrogen along the line-of-sight. We use a large suite of high…

Astrophysics · Physics 2009-11-10 James S. Bolton , Martin G. Haehnelt , Matteo Viel , Volker Springel

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

Our goal in this paper is to test some popular dark matter models by Ly-alpha forest in QSO spectra. Recent observations of the size and velocity of Ly-alpha forest clouds have indicated that the Ly-alpha absorption is probably not given by…

Astrophysics · Physics 2009-10-28 Hongguang BI , Jian GE , Li-Zhi FANG

Observations of the Lyman-$\alpha$ (Ly$\alpha$) forest from spectroscopic surveys such as BOSS/eBOSS, or the ongoing DESI, offer a unique window to study the growth of structure on megaparsec scales. Interpretation of these measurements is…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-09 Christian Pedersen , Andreu Font-Ribera , Nickolay Y. Gnedin

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

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.…

We use an automated Voigt-profile fitting procedure to extract statistical properties of the Ly$\alpha$ forest in a numerical simulation of an $\Omega=1$, cold dark matter (CDM) universe. Our analysis method is similar to that used in most…

Astrophysics · Physics 2007-05-23 Romeel Davé , Lars Hernquist , David H. Weinberg , Neal Katz