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Related papers: Distribution function of the dark matter

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We introduce a very simple model of a dark halo. It is a close relative of Hernquist's model, being generated by the same transformation but this time applied to the logarithmic potential rather than the point mass. The density is…

Astrophysics of Galaxies · Physics 2015-06-22 N. W. Evans , A. A. Williams

We study the differential energy distribution of dark matter halos, carrying out cosmological N-body simulation.We give an analytical formula of the differential energy distribution of dark matter in the halos obtained by the numerical…

Astrophysics · Physics 2009-10-31 Chiaki Hanyu , Asao Habe

Dark matter particles form halos that contribute the major part of the mass of galaxy clusters. The formation of these cosmological structures have been investigated both observationally and in numerical simulations, which have confirmed…

Astrophysics · Physics 2009-11-05 Ole Host

For a spherical dark matter halo with isotropic velocity distribution, the phase space distribution function (DF), the energy distribution, and the density profile form a set of self-consistent description of its equilibrium state, and…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-26 Axel Gross , Zhaozhou Li , Yong-Zhong Qian

We present measurements of the shape of the stellar line-of-sight velocity distribution out to two effective radii along the major axes of the four elliptical galaxies NGC 2434, 2663, 3706, and 5018. The velocity dispersion profiles are…

Astrophysics · Physics 2016-08-30 M. Carollo , T. de Zeeuw , R. van der Marel , J. Danziger , E. Qian

All dark matter structures appear to follow a set of universalities, such as phase-space density or velocity anisotropy profiles, however, the origin of these universalities remains a mystery. Any equilibrated dark matter structure can be…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Steen H. Hansen , Martin Sparre

Dark Matter (DM) direct detection experiments usually assume the simplest possible 'Standard Halo Model' for the Milky Way (MW) halo in which the velocity distribution is Maxwellian. This model assumes that the MW halo is an isotropic,…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-02 Mattia Fornasa , Anne M. Green

We demonstrate the existence of distribution functions that can be used to represent spherical massless cored stellar systems embedded in cuspy dark matter halos with constant mildly tangential velocity anisotropy. In particular, we derive…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Maarten A. Breddels , Amina Helmi

The velocity distribution of the dark matter particles on the outskirts of the Solar System remains unclear. We suggest to determine it using experimentally found properties of the oldest halo objects. Indeed, the oldest halo stars and…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Anton N. Baushev

A method is presented for finding anisotropic distribution functions for stellar systems with known, spherically symmetric, densities, which depends only on the two classical integrals of the energy and the magnitude of the angular…

Astrophysics · Physics 2008-12-31 Zhenglu Jiang , Leonid Ossipkov

We review the most recent evidence for the amazing properties of the density distribution of dark matter around spiral galaxies. Their rotation curves, coadded according to the galaxy luminosity, conform to an universal profile which can be…

Astrophysics · Physics 2007-05-23 P. Salucci , A. Borriello

We investigate a hypothesis regarding the origin of the scalelength in halos formed in cosmological N-body simulations. This hypothesis can be viewed as an extension of an earlier idea put forth by Merritt and Aguilar. Our findings suggest…

Astrophysics · Physics 2009-11-13 E. I. Barnes , L. L. R. Williams , A. Babul , J. J. Dalcanton

We present a new method to construct fully self-consistent equilibrium models of multi-component disc galaxies similar to the Milky Way. We define distribution functions for the stellar disc and dark halo that depend on phase space position…

Astrophysics of Galaxies · Physics 2015-07-03 T. Piffl , Z. Penoyre , J. Binney

In this paper, we present the density, \rho, velocity dispersion, \sigma, and \rho/\sigma^3 profiles of isotropic systems which have the energy distribution, N(E)\propto[\exp(\phi_0-E)-1], derived in Paper I. This distribution, dubbed…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Liliya L. R. Williams , Jens Hjorth

We derive the pairwise peculiar velocity distribution function of dark matter particles applying the dark matter halo approach. Unlike the previous work, we do not assume a Gaussian velocity distribution function of dark matter in a single…

Astrophysics · Physics 2015-06-24 Takeshi Kuwabara , Atsushi Taruya , Yasushi Suto

Using N-body simulations we study the phenomenon of radial orbit instability occurring in dark matter haloes of the size of a dwarf galaxy. We carried out simulations of seven spherical models, with the same standard NFW density profile but…

Astrophysics of Galaxies · Physics 2016-10-21 Grzegorz Gajda , Ewa L. Lokas , Radoslaw Wojtak

The one-point function (i.e., the isotropic flux distribution) is a complementary method to (anisotropic) two-point correlations in searches for a gamma-ray dark matter annihilation signature. Using analytical models of structure formation…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-02 Michael R. Feyereisen , Shin'ichiro Ando , Samuel K. Lee

Small-scale challenges to $\Lambda$CDM cosmology require a deeper understanding of dark matter physics.This paper aims to develop maximum entropy distributions for dark matter particle velocity (denoted by $X$), speed (denoted by $Z$), and…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-06 Zhijie Xu

The density profiles established in the self-similar dynamical phase of dark matter haloes recollapse are all close to isothermal. This is steeper than the predictions of some n-body simulations for the central regions of the halo, which…

Astrophysics · Physics 2009-11-07 R. N Henriksen , M. Le Delliou

The velocity distribution function (VDF) of dark matter (DM) halos in $\Lambda$CDM dissipationless cosmological simulations, which must be non-separable in its radial and tangential components, is still poorly known. We present the first…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-21 Leandro J. Beraldo e Silva , Gary A. Mamon , Manuel Duarte , Radoslaw Wojtak , Sébastien Peirani , Gwenaël Boué