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We clarify the subtle issue of finding the correct mapping of Newtonian simulations to light-cone observables at very large distance scales. A faithful general-relativistic interpretation specifies a gauge, i.e. a chart that relates the…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-17 Julian Adamek , Christian Fidler

Reconstructing cosmological initial conditions (ICs) from late-time observations is a difficult task, which relies on the use of computationally expensive simulators alongside sophisticated statistical methods to navigate multi-million…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-22 Oleg Savchenko , Florian List , Guillermo Franco Abellán , Noemi Anau Montel , Christoph Weniger

We present the results of the first N-body simulations of the Growing Neutrino scenario, as recently discussed in Baldi et al. (2011). Our results have shown for the first time how neutrino lumps forming in the context of Growing Neutrino…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-12 Marco Baldi

We intend to make sets of cosmological simulations available, with a large number of different output times that may be placed side-by-side to produce a complete history of the universe stretching back to high redshift. Currently there is…

Astrophysics · Physics 2007-05-23 P. A. Thomas , H. M. P. Couchman , F. R. Pearce

Accurate predictions for the non-linear matter power spectrum are needed to confront theory with observations in current and near future weak lensing and galaxy clustering surveys. We propose a computationally cheap method to create an…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-01 Hans Winther , Santiago Casas , Marco Baldi , Kazuya Koyama , Baojiu Li , Lucas Lombriser , Gong-Bo Zhao

The correspondence of single-field cosmological models based on Einstein gravity to modern observational data is considered. A method is proposed to determine possible types of dynamics based on extreme values of the scalar field. It is…

General Relativity and Quantum Cosmology · Physics 2025-10-10 I. V. Fomin

The cosmographic approach, which only relies upon the homogeneity and isotropy of the Universe on large scales, has become an essential tool in dealing with an increasing number of theoretical possibilities for explaining the late-time…

General Relativity and Quantum Cosmology · Physics 2016-04-26 Alvaro de la Cruz-Dombriz

Numerical N-body simulations of large scale structure formation in the universe are based on Newtonian gravity. However, according to our current understanding, the most correct theory of gravity is general relativity. It is therefore…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-27 Ugo Bertello

We present the first simulation capable of resolving the structure of neutrino clustering on Mpc scales. The method combines grid- and particle-based methods and achieves very good accuracy on both small and large scales, while keeping CPU…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Jacob Brandbyge , Steen Hannestad

Gravitational N-body simulations, that is numerical solutions of the equations of motions for N particles interacting gravitationally, are widely used tools in astrophysics, with applications from few body or solar system like systems all…

Astrophysics · Physics 2008-06-25 M. Trenti , P. Hut

A detailed analysis of dynamics of cosmological models based on $R^{n}$ gravity is presented. We show that the cosmological equations can be written as a first order autonomous system and analyzed using the standard techniques of dynamical…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Carloni , P. K. S. Dunsby , S. Capozziello , A. Troisi

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified…

Astrophysics · Physics 2015-05-13 J. C. Fabris , S. V. B. Goncalves , H. E. S. Velten , W. Zimdahl

Neutrinos coupled to an underlying scalar field in the scenario for unification of mass varying dark matter and cosmon-{\em like} dark energy is examined. In the presence of a tiny component of mass varying neutrinos, the conditions for the…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-15 Alex E. Bernardini

Although the MiniBooNE experiment has severely restricted the possible existence of light sterile neutrinos, a few anomalies persist in oscillation data, and the possibility of extra light species contributing as a subdominant hot (or warm)…

Astrophysics · Physics 2010-04-23 Mario A. Acero , Julien Lesgourgues

In this paper we present the implementation of an efficient formalism for the generation of arbitrary non-Gaussian initial conditions for use in N-body simulations. The methodology involves the use of a separable modal approach for…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 D. M. Regan , M. M. Schmittfull , E. P. S. Shellard , J. R. Fergusson

Recent work has highlighted the potentially detectable gravitational-lensing effect of neutrino halos on cosmic-microwave-background (CMB) fluctuations with upcoming instruments like SO, CMB-S4, and CMB-HD. Accurate modeling of…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-14 Keduse Worku , Nashwan Sabti , Marc Kamionkowski

A class of cosmological solutions of higher dimensional Einstein field equations with the energy-momentum tensor of a homogeneous, isotropic fluid as the source are considered with an anisotropic metric that includes the direct sum of a…

General Relativity and Quantum Cosmology · Physics 2013-10-24 Ozgur Akarsu , Tekin Dereli

We present cosmological perturbation theory in neutrinos probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is…

Astrophysics · Physics 2009-06-23 Kiyotomo Ichiki , Yong-Yeon Keum

The assumption of a flat Universe that follows the cosmological principle, i.e., that the universe is statistically homogeneous and isotropic at large scales, comprises one of the core foundations of the standard cosmological model --…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-24 Mariana L. S. Dias , Antônio F. B. da Cunha , Carlos A. P. Bengaly , Rodrigo S. Gonçalves , Jonathan Morais

A variety of gauges are used in cosmological perturbation theory. These are often chosen in order to attribute physical properties to a particular choice of coordinates, or otherwise to simplify the form of the resultant equations.…

General Relativity and Quantum Cosmology · Physics 2020-04-01 Timothy Clifton , Christopher S. Gallagher , Sophia Goldberg , Karim A. Malik