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We present the results of cosmological simulations of large-scale structure formation with massive neutrinos. The phase-space distribution of the cosmic relic neutrinos is followed, for the first time, by directly integrating the…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-09 Kohji Yoshikawa , Satoshi Tanaka , Naoki Yoshida , Shun Saito

An overview over the current status of modeling galaxies by means of numerical simulations is given. After a short description of how galaxies form in hierarchically clustering scenarios, success and failures of current simulations are…

Astrophysics · Physics 2007-05-23 Matthias Steinmetz

Analysis of large galaxy surveys requires confidence in the robustness of numerical simulation methods. The simulations are used to construct mock galaxy catalogs to validate data analysis pipelines and identify potential systematics. We…

We present the second-order general relativistic description of the observed galaxy number density in a cosmological framework. The observed galaxy number density is affected by the volume and the source effects, both of which arise due to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Jaiyul Yoo , Matias Zaldarriaga

Laboratory experiments on gravitation are usually performed with objects of constant density, so that the analysis of the forces concerns only the geometry of their shape. In an ideal experiment, the shapes of the constituent parts will be…

General Relativity and Quantum Cosmology · Physics 2007-05-23 John W. Barrett

In this paper, we analyze the clustering of galaxies using a modified theory of gravity, in which the field content of general relativity has been be increased. This increasing in the field content of general relativity changes the large…

General Relativity and Quantum Cosmology · Physics 2019-11-06 Mir Hameeda , Behnam Pourhassan , Mir Faizal , C. P. Masroor , Rizwan Ul Haq Ansari , P. K. Suresh

Cosmological N-body simulations have been a major tool of theorists for decades, yet many of the numerical issues that these simulations face are still unexplored. This paper measures numerical biases in these large, dark matter-only…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-11 Philip Mansfield , Camille Avestruz

We provide the differential equations that generalize the Newtonian N-body problem of celestial mechanics to spaces of constant Gaussian curvature, k, for all k real. In previous studies, the equations of motion made sense only for k…

Dynamical Systems · Mathematics 2019-08-15 Florin Diacu

The N-body problem is a classic problem involving a system of N discrete bodies mutually interacting in a dynamical system. At any moment in time there are N*(N - 1)/2 such interactions occurring. This scaling as N^2 leads to computational…

Computational Engineering, Finance, and Science · Computer Science 2022-03-18 Alexander Brandt

The N-body gauge allows the introduction of relativistic effects in Newtonian cosmological simulations. Here we extend this framework to general Horndeski gravity theories, and investigate the relativistic effects that the scalar field…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-22 Guilherme Brando , Kazuya Koyama , David Wands , Miguel Zumalacárregui , Ignacy Sawicki , Emilio Bellini

We review the field of collisionless numerical simulations for the large-scale structure of the Universe. We start by providing the main set of equations solved by these simulations and their connection with General Relativity. We then…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-14 Raul E. Angulo , Oliver Hahn

The observed flat rotation curves of galaxies require either the presence of dark matter in Newtonian gravitational potentials or a significant modification to the theory of gravity at galactic scales. Detecting relativistic Doppler shifts…

Astrophysics of Galaxies · Physics 2012-02-15 Alan Cooney , Dimitrios Psaltis , Dennis Zaritsky

The large-scale clustering of galaxies can serve as a probe of primordial non-Gaussianity in the Universe competitive with the anisotropies of the CMB. Here, we present improved theoretical predictions which include an important, previously…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Vincent Desjacques , Donghui Jeong , Fabian Schmidt

A persistent theme in the study of dark energy is the question of whether it really exists or not. It is often claimed hat we are mis-calculating the cosmological model by neglecting the effects associated with averaging over large-scale…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-07 Julian Adamek , Chris Clarkson , David Daverio , Ruth Durrer , Martin Kunz

Numerical hydro-N-body simulations are very important tools for making theoretical predictions for the formation of galaxy clusters. They show that the atmospheres of clusters of galaxies have quite complex angular and thermal structures.…

Astrophysics · Physics 2009-11-10 A. Gardini , E. Rasia , P. Mazzotta , G. Tormen , S. De Grandi , L. Moscardini

We simulate the assembly of a massive rich cluster and the formation of its constituent galaxies in a flat, low-density universe. Our most accurate model follows the collapse, the star-formation history and the orbital motion of all…

Astrophysics · Physics 2009-09-25 Volker Springel , Simon White , Giuseppe Tormen , Guinevere Kauffmann

Based on thermodynamics, we discuss the galactic clustering of expanding Universe by assuming the gravitational interaction through the modified Newton's potential given by $f(R)$ gravity. We compute the corrected $N$-particle partition…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-22 Salvatore Capozziello , Mir Faizal , Mir Hameeda , Behnam Pourhassan , Vincenzo Salzano , Sudhaker Upadhyay

Numerical simulations play a key important role in modern cosmology. Examples are plenty including the cosmic web - large scale structure of the distribution of galaxies in space - which was first observed in N-body simulations and later…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-07 Anatoly Klypin , Francisco Prada , Johan Comparat

Tormen and Bertschinger have presented an algorithm which allows the dynamic range of N-body simulations to be extended by adding long-wavelength power to an evolved N-body simulation. This procedure is of considerable interest as it will…

Astrophysics · Physics 2015-06-24 Shaun Cole

The cosmological many-body problem is effectively an infinite system of gravitationally interacting masses in an expanding universe. Despite the interactions' long-range nature, an analytical theory of statistical mechanics describes the…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-01 W. C. Saslaw , A. Yang