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The systematic magnification of background sources by the weak gravitational-lensing effects of foreground matter, also called cosmic magnification, is becoming an efficient tool both for measuring cosmological parameters and for exploring…

Astrophysics · Physics 2015-06-24 Brice Menard , Takashi Hamana , Matthias Bartelmann , Naoki Yoshida

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,…

It is shown how wavelets may be used to analyse the absorption properties of the Lya forest. The Discrete Wavelet Transform of a QSO spectrum is used to decompose the light fluctuations that comprise the forest into orthogonal wavelets. It…

Astrophysics · Physics 2009-10-31 A. Meiksin

We investigate possible systematic errors in the recent measurement of the matter power spectrum from the Lyman-alpha forest by Croft et al. (2001). We find that for a large set of prior cosmological models the Croft et al. result holds…

Astrophysics · Physics 2009-11-07 Nickolay Y. Gnedin , Andrew J. S. Hamilton

Cosmological analyses of second-order weak lensing statistics require precise and accurate covariance estimates. These covariances are impacted by two sometimes neglected terms: A negative contribution to the Gaussian covariance due to…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-04 Laila Linke , Pierre A. Burger , Sven Heydenreich , Lucas Porth , Peter Schneider

We propose an anisotropic generalisation of the line correlation function (ALCF) to separate and quantify phase information in the large-scale structure of galaxies. The line correlation function probes the strictly non-linear regime of…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-22 Alexander Eggemeier , Thorsten Battefeld , Robert E. Smith , Jens Niemeyer

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 analysis of the Lyman-alpha forest of absorption lines in quasar spectra has emerged as a potentially powerful technique to constrain the linear matter power spectrum. In most previous work, the amplitude of the ionizing background was…

Astrophysics · Physics 2009-11-11 Adam Lidz , Katrin Heitmann , Lam Hui , Salman Habib , Michael Rauch , Wallace L. W. Sargent

Linear scaling quantum chemical methods for Density Functional Theory are extended to the condensed phase at the $\Gamma$-point. For the two-electron Coulomb matrix, this is achieved with a tree-code algorithm for fast Coulomb summation [J.…

Materials Science · Physics 2009-11-10 C. J. Tymczak , Matt Challacombe

We directly measure the evolution of the intergalactic Lyman-alpha effective optical depth, tau_eff, over the redshift range 2<z<4.2 from a sample of 86 high-resolution, high-signal-to-noise quasar spectra obtained with Keck/ESI,…

Astrophysics · Physics 2010-11-11 C. -A. Faucher-Giguere , J. X. Prochaska , A. Lidz , L. Hernquist , M. Zaldarriaga

We present the calculation of the Lyman-alpha (Lyman-$\alpha$) transmitted flux fluctuations with full relativistic corrections to the first order. Even though several studies exist on relativistic effects in galaxy clustering, this is the…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-24 Vid Iršič , Enea Di Dio , Matteo Viel

We simulate the Lya forest in a standard CDM universe using a 2-level hierarchical grid code to evolve the dark and baryonic matter components self-consistently. We solve the time-dependent ionization equations for hydrogen and helium,…

Astrophysics · Physics 2009-10-28 Yu Zhang , Peter Anninos , Michael L. Norman , Avery Meiksin

The K function and its related statistics have been an enduring tool in the analysis of spatial point processes, providing an easy to compute and interpret summary statistic for characterising the interactions between points of one type, or…

Methodology · Statistics 2026-05-20 Jake P. Grainger , Tuomas A. Rajala , David J. Murrell , Sofia C. Olhede

Lyman alpha absorber correlations contain information about the underlying density distribution associated with a particular class of absorbers. As such, they provide an opportunity to independently measure the "bias" of the Lyman alpha…

Astrophysics · Physics 2016-01-27 Romeel Davé , Neal Katz , David H. Weinberg

The next frontier of Lyman-alpha forest studies is the reconstruction of 3D correlations from a dense sample of background sources. The measurement of 3D correlations has the potential to improve constraints on fundamental cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Matthew McQuinn , Martin White

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 present a theoretical formalism to predict the two-point clustering statistics (the power spectrum and the two-point correlation function), simultaneously taking account of the linear velocity distortion, the nonlinear velocity…

Astrophysics · Physics 2015-06-24 Yasushi Suto , Hiromitsu Magira , Kazuhiro Yamamoto

The three-dimensional distribution of the Ly$\alpha$ forest has been extensively used to constrain cosmology through measurements of the baryon acoustic oscillations (BAO) scale. However, more cosmological information could be extracted…

We investigate the cross-correlation signal between 21cm intensity mapping maps and the Lyman-alpha forest in the fully non-linear regime using state-of-the-art hydrodynamic simulations. The cross-correlation signal between these fields can…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-06 Isabella P. Carucci , Francisco Villaescusa-Navarro , Matteo Viel
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