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Cosmological perturbation theory for the late Universe dominated by dark matter is extended beyond the perfect fluid approximation by taking the dark matter velocity dispersion tensor as an additional field into account. A proper tensor…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-04 Alaric Erschfeld , Stefan Floerchinger

We compute the dark matter velocity dispersion tensor up to third order in perturbation theory using the Lagrangian formalism, revealing growing solutions at the third and higher orders. Our results are general and can be used for any other…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-30 Alejandro Aviles

We explore the growth of structure in multi-species wave (and particle) dark matter. We derive the evolution of the power spectrum of total density contrasts for an arbitrary number of component species, density fractions, and initial field…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-21 Mustafa A. Amin , M. Sten Delos

The primordial velocity dispersion of dark matter is small compared to the velocities attained during structure formation. The initial density distribution is close to uniform and it occupies an initial sheet in phase space that is single…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Tom Abel , Oliver Hahn , Ralf Kaehler

We investigate the evolution of density perturbations in dark matter, including the new combined effects of finite number density and non-zero velocity dispersion. Using a truncated BBGKY hierarchy, we derive analytical expressions for the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Mustafa A. Amin , M. Sten Delos , Mehrdad Mirbabayi

We compute the generation of vorticity from velocity dispersion in the dark matter fluid. For dark matter at zero temperature Helmholtz's theorem dictates that no vorticity is generated and we therefore allow the dark matter fluid to have a…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-05 Giulia Cusin , Vittorio Tansella , Ruth Durrer

We present a general analytic framework for the evolution of cosmic structure in multi-species dark matter models that simultaneously incorporates finite velocity dispersion and Poisson fluctuations. Our approach accommodates arbitrary…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 Mustafa A. Amin , M. Sten Delos , Kaixin Yang

Dark matter, if exists, accounts for five times as much as the ordinary baryonic matter. Compared to hydrodynamic turbulence, the flow of dark matter might possess the widest presence in our universe. This paper presents a statistical…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-10 Zhijie Xu

We discuss the propagation of dark matter perturbations with non-zero velocity dispersion in cosmological models. In particular a non-zero massive neutrino component may well have a significant effect on the matter power spectrum and cosmic…

Astrophysics · Physics 2009-11-07 Antony Lewis , Anthony Challinor

The evolution of the large scale distribution of matter in the universe is often characterized by the density field. Here we take a complimentary approach and characterize it using the cosmic velocity field, specifically the deformation of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Noam I Libeskind , Yehuda Hoffman , Stefan Gottlöber

Residual velocity dispersion in cold dark matter induces stresses which lead to effects that are absent in the idealized dust model. A previous Newtonian analysis showed how this approach can provide a theoretical foundation for the…

Astrophysics · Physics 2016-08-25 Roy Maartens , Josep Triginer , David Matravers

In this work the dynamics of self-gravitating systems composed by dark and baryonic matter is analyzed. Searching for a description of this dynamics, a system of collisionless Boltzmann equations for the two constituents and the Poisson…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-11 Gilberto M. Kremer , Raíla André

In this work we present a model of dark matter based on scalar-tensor theory of gravity. With this scalar field dark matter model we study the non-linear evolution of the large scale structures in the universe. The equations that govern the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Mario A. Rodriguez-Meza

This paper studies the scale and redshift variation of density and velocity distributions in self-gravitating collisionless dark matter flow by a halo-based non-projection approach. All particles are divided into halo and out-of-halo…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-28 Zhijie Xu

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

We analyse the evolution of cosmological perturbations which leads to the formation of large isolated voids in the Universe. We assume that initial perturbations are spherical and all components of the Universe (radiation, matter and dark…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Bohdan Novosyadlyj , Maksym Tsizh , Yurij Kulinich

We present an analytical and numerical study of the velocity distribution function of self gravitating collisionless particles, which include dark matter and star clusters. We show that the velocity distribution derived through the…

Astrophysics · Physics 2012-06-22 Steen H. Hansen , Daniel Egli , Lukas Hollenstein , Christoph Salzmann

The infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-18 Nilanjan Banik , Pierre Sikivie

We study the generation of vorticity and velocity dispersion by orbit crossing using cosmological numerical simulations, and calculate the backreaction of these effects on the evolution of large-scale density and velocity divergence power…

Astrophysics · Physics 2009-09-02 Sebastian Pueblas , Roman Scoccimarro

The strongest evidence for dark energy comes presently from geometric techniques such as the supernova distance-redshift relation. By combining the measured expansion history with the Friedmann equation one determines the energy density and…

Astrophysics · Physics 2008-11-26 Edmund Bertschinger
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