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Cosmological backreaction suggests a link between structure formation and the expansion history of the Universe. In order to quantitatively examine this connection, we dynamically investigate a volume partition of the Universe into over--…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-18 Alexander Wiegand , Thomas Buchert

The large-scale statistics of observables such as the galaxy density are chiefly determined by their dependence on the local coarse-grained matter density. This dependence can be measured directly and efficiently in N-body simulations by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Christian Wagner , Fabian Schmidt , Chi-Ting Chiang , Eiichiro Komatsu

We study structure formation in the late Universe within the Vlasov kinetic self-consistent field approach. Our work is principally focused on the use of the modified gravitational potential with a repulsive term of the cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-28 V. G. Gurzadyan , N. N. Fimin , V. M. Chechetkin

We propose a lightweight deep convolutional neural network (lCNN) to estimate cosmological parameters from simulated three-dimensional dark matter (DM) halo distributions and associated statistics. The training dataset comprises 2000…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-20 Zhiwei Min , Xu Xiao , Jiacheng Ding , Liang Xiao , Jie Jiang , Donglin Wu , Qiufan Lin , Yang Wang , Shuai Liu , Zhixin Chen , Xiangru Li , Jinqu Zhang , Le Zhang , Xiao-Dong Li

We calculate the power spectrum of density fluctuations in the statistical non-equilibrium field theory for classical, microscopic degrees of freedom to first order in the interaction potential. We specialise our result to cosmology by…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-07 Matthias Bartelmann , Felix Fabis , Daniel Berg , Elena Kozlikin , Robert Lilow , Celia Viermann

Our goal is to see how density waves of different scale combine to form voids between galaxy systems of various scale. We perform numerical simulations of structure formation in cubes of size 100 and 256 Mpc/h, with resolutions 256^3 and…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-13 J. Einasto , I. Suhhonenko , G. Hütsi , E. Saar , M. Einasto , L. J. Liivamägi , V. Müller , A. A. Starobinsky , E. Tago , E. Tempel

Recently, the observed cellular nature of the large-scale structure of the Universe with its quasi-regular pattern of superclusters and voids has been pointed out by several authors. In this paper, we investigate properties of the initial…

Astrophysics · Physics 2019-08-17 P. Frisch , J. Einasto , M. Einasto , W. Freudling , K. J. Fricke , M. Gramann , V. Saar , O. Toomet

Understanding the physics of large cosmological surveys down to small (nonlinear) scales will significantly improve our knowledge of the Universe. Large N-body simulations have been built to obtain predictions in the non-linear regime.…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Chang Chen , Yin Li , Francisco Villaescusa-Navarro , Shirley Ho , Anthony Pullen

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

Strong gravitational lensing is a promising probe of the substructure of dark matter halos. Deep learning methods have the potential to accurately identify images containing substructure, and differentiate WIMP dark matter from other well…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-09 Stephon Alexander , Sergei Gleyzer , Evan McDonough , Michael W. Toomey , Emanuele Usai

How is the universe organized on large scales? How did this structure evolve from the unknown initial conditions to the present time? The answers to these questions will shed light on the cosmology we live in, the amount, composition and…

Astrophysics · Physics 2009-09-25 Neta A. Bahcall

Large-scale structure formation can be modeled as a nonlinear process that transfers energy from the largest scales to successively smaller scales until it is dissipated, in analogy with Kolmogorov's cascade model of incompressible…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jose Gaite

Density perturbations related to structure formations are expected to be different in dissipative and non-dissipative universes, even if the background evolution of the two universes is the same. To clarify the difference between the two…

General Relativity and Quantum Cosmology · Physics 2021-01-27 Nobuyoshi Komatsu

The DGP brane-world model provides an alternative to the standard LCDM cosmology, in which the late universe accelerates due to a modification of gravity rather than vacuum energy. The cosmological constant $\Lambda$ in LCDM is replaced by…

Astrophysics · Physics 2009-11-13 Kazuya Koyama , Roy Maartens

Next-generation galaxy surveys promise unprecedented precision in testing gravity at cosmological scales. However, realising this potential requires accurately modelling the non-linear cosmic web. We address this challenge by exploring…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-20 Julieth Katherine Riveros , Paola Saavedra , Hector J. Hortua , Jorge Enrique Garcia-Farieta , Ivan Olier

We investigate the characteristics and the time evolution of the cosmic web from redshift, z=2, to present time, within the framework of the NEXUS+ algorithm. This necessitates the introduction of new analysis tools optimally suited to…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-19 Marius Cautun , Rien van de Weygaert , Bernard J. T. Jones , Carlos S. Frenk

The last 20 years have seen an explosion in our understanding of the large-scale distribution and motions of galaxies in the nearby universe. The field has moved from a largely qualitative, morphological description of the structures seen…

Astrophysics · Physics 2007-05-23 Michael A. Strauss

This paper investigates the phenomenon of emergence of spatial curvature. This phenomenon is absent in the Standard Cosmological Model, which has a flat and fixed spatial curvature (small perturbations are considered in the Standard…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-01 Krzysztof Bolejko

The major uncertainties in studies of the multi-scale structure of the Universe arise not from observational errors but from the variety of legitimate definitions and detection methods for individual structures. To facilitate the study of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 M. J. Way , P. R. Gazis , Jeffrey D. Scargle

We present a brief history of the construction of models of the universe, followed by calculations of quantitative characteristics of basic geometric and kinematic properties of the Standard Cosmological Model ($\Lambda$CDM). Using the…

General Relativity and Quantum Cosmology · Physics 2026-04-23 D. I. Nagirner , S. G. Jorstad , A. V. Dementyev