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We describe a novel end-to-end approach using Machine Learning to reconstruct the power spectrum of cosmological density perturbations at high redshift from observed quasar spectra. State-of-the-art cosmological simulations of structure…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Maria Han Veiga , Xi Meng , Oleg Y. Gnedin , Nickolay Y. Gnedin , Xun Huan

Reconstruction techniques are commonly used in cosmology to reduce complicated nonlinear behaviours to a more tractable linearized system. We study a new reconstruction technique that uses the Moving-Mesh algorithm to estimate the…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-21 Qiaoyin Pan , Ue-Li Pen , Derek Inman , Hao-Ran Yu

In the pursuit of primordial non-Gaussianities, we hope to access smaller scales across larger comoving volumes. At low redshift, the search for primordial non-Gaussianities is hindered by gravitational collapse, to which we often associate…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-08 Thomas Flöss , Matteo Biagetti , P. Daniel Meerburg

Gaussian processes are a fully Bayesian smoothing technique that allows for the reconstruction of a function and its derivatives directly from observational data, without assuming a specific model or choosing a parameterization. This is…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-27 Marina Seikel , Chris Clarkson

We present COSMIC BIRTH: COSMological Initial Conditions from Bayesian Inference Reconstructions with THeoretical models: an algorithm to reconstruct the primordial and evolved cosmic density fields from galaxy surveys on the light-cone.…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-23 Francisco-Shu Kitaura , Metin Ata , Sergio A. Rodriguez-Torres , Monica Hernandez-Sanchez , A. Balaguera-Antolinez , Gustavo Yepes

We investigated the use of a U-Net convolutional neural network for denoising simulated medium-resolution spectroscopic observations of stars. Simulated spectra were generated under realistic observational conditions resembling the Subaru…

Instrumentation and Methods for Astrophysics · Physics 2025-04-04 Balázs Pál , László Dobos

We develop a general formalism for analysing parameter information from non-Gaussian cosmic fields. The method can be adapted to include the nonlinear effects in galaxy redshift surveys, weak lensing surveys and cosmic velocity field…

Astrophysics · Physics 2009-10-31 Andy Taylor , Peter Watts

The goal of the present paper is to set initial conditions for structure formation at non-linear order, consistent with general relativity, while also allowing for primordial non-Gaussianity. We use the non-linear continuity and Raychauduri…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Marco Bruni , Juan Carlos Hidalgo , Nikolai Meures , David Wands

The present work is based on a parametric reconstruction of the deceleration parameter $q(z)$ in a model for the spatially flat FRW universe filled with dark energy and non-relativistic matter. In cosmology, the parametric reconstruction…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Abdulla Al Mamon , Sudipta Das

We present an extension of our recently developed Wasserstein optimized model to emulate accurate high-resolution features from computationally cheaper low-resolution cosmological simulations. Our deep physical modelling technique relies on…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-17 Doogesh Kodi Ramanah , Tom Charnock , Francisco Villaescusa-Navarro , Benjamin D. Wandelt

A large number of cosmological parameters have been suggested for obtaining information on the nature of dark energy. In this work, we study the efficacy of these different parameters in discriminating theoretical models of dark energy,…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-08 Alexander V. Pan , Ujjaini Alam

We study the information content of summary statistics built from the multi-scale topology of large-scale structures on primordial non-Gaussianity of the local and equilateral type. We use halo catalogs generated from numerical N-body…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-05 Matteo Biagetti , Juan Calles , Lina Castiblanco , Alex Cole , Jorge Noreña

We present measurements of the dark matter bispectrum in N-body simulations with non-Gaussian initial conditions of the local kind for a large variety of triangular configurations and compare them with predictions from Eulerian Perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Emiliano Sefusatti , Martin Crocce , Vincent Desjacques

Reconstructing the Gaussian initial conditions at the beginning of the Universe from the survey data in a forward modeling framework is a major challenge in cosmology. This requires solving a high dimensional inverse problem with an…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-28 Chirag Modi , François Lanusse , Uroš Seljak , David N. Spergel , Laurence Perreault-Levasseur

We develop a field-level posterior for cosmological data by marginalizing over initial conditions and noise in a general forward model. While our focus is on large-scale structure data, the results generalize to any weakly non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-29 Massimo Pietroni , Fabian Schmidt

We computed the power spectrum of weak cosmic shear in models with non-Gaussian primordial density fluctuations. Cosmological initial conditions deviating from Gaussianity have recently attracted much attention in the literature, especially…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 C. Fedeli , L. Moscardini

We develop a purely mathematical tool to recover some of the information lost in the non-linear collapse of large-scale structure. From a set of 141 simulations of dark matter density fields, we construct a non-linear Weiner filter in order…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Tong-Jie Zhang , Hao-Ran Yu , Joachim Harnois-Déraps , Ilana MacDonald , Ue-Li Pen

We present a hybrid method for reconstructing the primordial density from late-time halos and galaxies. Our approach involves two steps: (1) apply standard Baryon Acoustic Oscillation (BAO) reconstruction to recover the large-scale features…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-03 Liam Parker , Adrian E. Bayer , Uros Seljak

Semi-numerical simulations are the leading candidates for evolving reionization on cosmological scales. These semi-numerical models are efficient in generating large-scale maps of the 21cm signal, but they are too slow to enable inference…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-22 Mosima P. Masipa , Sultan Hassan , Mario G. Santos , Gabriella Contardo , Kyunghyun Cho

We consider primordial non-Gaussianity due to quadratic corrections in the gravitational potential parametrized by a non-linear coupling parameter fnl. We study constraints on fnl from measurements of the galaxy bispectrum in redshift…

Astrophysics · Physics 2009-11-10 Roman Scoccimarro , Emiliano Sefusatti , Matias Zaldarriaga
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