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An approach to cosmological modelling is presented that incorporates the inhomogeneous structure of the Cosmic Web, specifically focusing on the interplay between cosmic voids and density walls. We extend the standard homogeneous and…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-12 John Moffat

Local nonlinear approximations to the growth of cosmic perturbations are developed, resulting in relations, at a given epoch, between the peculiar velocity and gravity fields and their gradients. Only the equation of motion is approximated,…

Astrophysics · Physics 2009-10-22 Paul J. Mancinelli , Amos Yahil

We classify singularities in FRW cosmologies, which dynamics can be reduced to the dynamical system of the Newtonian type. This classification is performed in terms of geometry of a potential function if it has poles. At the sewn…

General Relativity and Quantum Cosmology · Physics 2017-09-29 Aleksander Stachowski , Marek Szydlowski , Andrzej Borowiec

We use numerical relativity simulations to describe the spacetime evolution during nonlinear structure formation in $\Lambda$CDM cosmology. Fully nonlinear initial conditions are set at an initial redshift $z\approx 300$, based directly on…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-12 Robyn L. Munoz , Marco Bruni

We study the nonlinear gravitational dynamics of a universe filled with a pressureless fluid and a cosmological constant $\Lambda$ in the context of Newtonian gravity, and in the relativistic post-Friedmann approach proposed in paper I [I.…

General Relativity and Quantum Cosmology · Physics 2016-10-26 Cornelius Rampf , Eleonora Villa , Daniele Bertacca , Marco Bruni

The Zeldovich approximation is applied to study the accretion of hot and cold dark matter onto moving long strings. It is assumed that such defects carry a substantial amount of small-scale structure, thereby acting gravitationally as a…

Astrophysics · Physics 2009-12-30 V. Zanchin , J. A. S. Lima , R. Brandenberger

A new approach for the classification of the cosmic web is presented. In extension of the previous work of Hahn et al. (2007) and Forero-Romero et al. (2009) the new algorithm is based on the analysis of the velocity shear tensor rather…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-17 Yehuda Hoffman , Ofer Metuki , Gustavo Yepes , Stefan Gottlöber , Jaime E. Forero-Romero , Noam I. Libeskind , Alexander Knebe

We discuss various analytical approximation methods for the evolution of the density fluctuation in the Universe. From primordial density fluctuation, the large-scale structure is formed via its own self-gravitational instability. For this…

Astrophysics · Physics 2007-05-23 Takayuki Tatekawa

The presence of complex hierarchical gravitational structures is one of the main features of the observed universe. Here, structure formation is studied both for the standard ($\Lambda \rm CDM$) cosmological model and for the Dirac-Milne…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Giovanni Manfredi , Jean-Louis Rouet , Bruce N. Miller , Gabriel Chardin

Modelling structure formation across the full dynamical range of the Universe remains a major challenge in cosmology. This difficulty originates from a fundamental limitation of geodesics in general relativity: a one-parameter family of…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-16 Obinna Umeh

The spatial cosmic matter distribution on scales of a few up to more than a hundred Megaparsec displays a salient and pervasive foamlike pattern. Voronoi tessellations are a versatile and flexible mathematical model for such weblike spatial…

Astrophysics · Physics 2007-07-20 Rien van de Weygaert

The lecture notes describe the Delaunay Tessellation Field Estimator for Cosmic Web analysis. The high sensitivity of Voronoi/Delaunay tessellations to the local point distribution is used to obtain estimates of density and related…

Astrophysics · Physics 2017-03-08 Rien van de Weygaert , Willem Schaap

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

The Sunyaev-Zel'dovich effect (SZE) provides a unique way to map the large-scale structure of the universe as traced by massive clusters of galaxies. As a spectral distortion of the cosmic microwave background, the SZE is insensitive to the…

Astrophysics · Physics 2011-05-05 John E. Carlstrom , Gilbert P. Holder , Erik D. Reese

Aims. We investigate how properties of the ensemble of superclusters in the cosmic web evolve with time. Methods. We perform numerical simulations of the evolution of the cosmic web using the LambdaCDM model in box sizes L0 = 1024, 512, 256…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-13 J. Einasto , I. Suhhonenko , L. J. Liivamägi , M. Einasto

In the context of the cosmological and constrained ELUCID simulation, this study explores the statistical characteristics of filaments within the cosmic web, focussing on aspects such as the distribution of filament lengths and their radial…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-21 Youcai Zhang , Hong Guo , Xiaohu Yang , Peng Wang

In the current cosmological paradigm, an initially flat three-dimensional manifold that pervades space (the `dark-matter sheet') folds up to build concentrations of mass (galaxies), and a cosmic web between them. Galaxies are nodes,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Mark C. Neyrinck

We perform an analysis of the Cosmic Web as a complex network, which is built on a $\Lambda$CDM cosmological simulation. For each of nodes, which are in this case dark matter halos formed in the simulation, we compute 10 network metrics,…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Maksym Tsizh , Bohdan Novosyadlyj , Yurij Holovatch , Noam I Libeskind

I present a comprehensive review of the evolution of galaxy structure in the universe from the first galaxies we can currently observe at z~6 down to galaxies we see in the local universe. I further address how these changes reveal galaxy…

Astrophysics of Galaxies · Physics 2015-06-19 Christopher J. Conselice

We compare relativistic approximation methods, which describe gravitational instability in the expanding universe, in a spherically symmetric model. Linear perturbation theory, second-order perturbation theory, relativistic Zel'dovich…

Astrophysics · Physics 2014-10-13 Masaaki Morita , Kouji Nakamura , Masumi Kasai