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We use the recently completed one billion particle Via Lactea II LambdaCDM simulation to investigate local properties like density, mean velocity, velocity dispersion, anisotropy, orientation and shape of the velocity dispersion ellipsoid,…

We present a useful function for describing the profiles of dark-matter haloes with a varying asymptotic inner slope -\alpha, ranging from a cusp to a core, where the profiles of density, mass-velocity and potential are simple analytic…

Astrophysics of Galaxies · Physics 2016-10-06 Avishai Dekel , Guy Ishai , Aaron A. Dutton , Andrea V. Maccio

An estimate of the convergence radius of a simulated CDM halo is obtained under the assumption that the peak phase-space density in the system is set by discreteness effects that operate prior to relaxation. The predicted convergence radii…

Astrophysics · Physics 2009-11-10 James Binney

Many dynamical models of the Milky Way halo require assumptions that the distribution function of a tracer population should be independent of time (i.e., a steady state distribution function) and that the underlying potential is spherical.…

Astrophysics of Galaxies · Physics 2017-07-28 Wenting Wang , Jiaxin Han , Shaun Cole , Carlos Frenk , Till Sawala

Several lines of evidence suggest that cold, dense gas clouds make a substantial contribution to the total mass of dark halos. If so then physical collisions between clouds must occur; these cause strong, radiative shocks to propagate…

Astrophysics · Physics 2007-05-23 Mark A. Walker

Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters of the orbit, or decay…

Astrophysics · Physics 2010-04-15 Niayesh Afshordi , Roya Mohayaee , Edmund Bertschinger

Quantitative modeling of the spectro-spatial distributions of energetic electrons and protons in galactic halos is needed in order to determine their interactions with the local plasma and radiation fields, and also to estimate their…

High Energy Astrophysical Phenomena · Physics 2019-04-17 Yoel Rephaeli , Sharon Sadeh

(Context) In a Universe dominated by dark matter, halos are continuously accreting mass (violently or not) and such mechanism affects their dynamical state. (Aims) The evolution of dark matter halos in phase-space, and using the phase-space…

Astrophysics · Physics 2009-05-03 S. Peirani , J. A. de Freitas Pacheco

We use a high resolution $\Lambda$CDM numerical simulation to calculate the mass function of dark matter haloes down to the scale of dwarf galaxies, back to a redshift of fifteen, in a 50 $h^{-1}$Mpc volume containing 80 million particles.…

The idea of self-interacting bosonic dark matter capable of exhibiting superfluidity is revisited. We show that the most interesting parameter space of the theory corresponds to fully thermalized dark matter halos. As a result the entire…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-21 Lasha Berezhiani , Giordano Cintia , Justin Khoury

We present the HI data for 5 spiral galaxies that, along with their Halpha rotation curves, are used to derive the distribution of dark matter within these objects. A new method for extracting rotation curves from HI data cubes is…

Astrophysics · Physics 2009-11-10 G. Gentile , P. Salucci , U. Klein , D. Vergani , P. Kalberla

Thanks to the ever increasing computational power and the development of more sophisticated algorithms, numerical N-body simulations are now uncovering several phenomenological relations between the physical properties of dark matter haloes…

Astrophysics · Physics 2009-11-13 Yago Ascasibar , Stefan Gottloeber

The dissipative infall of gas during the formation of a galaxy modifies the density profile and shape of the dark halo. Gas dissipates energy radiatively and sinks to the center of the dark halo forming the luminous part of a galaxy. The…

Astrophysics · Physics 2009-10-22 John Dubinski

(Abridged) We report results of a series of non radiative N-body/SPH simulations in a LCDM cosmology. We find that the spin of the baryonic component is on average larger than that of the dark matter (DM) component and we find this effect…

Astrophysics · Physics 2009-11-10 Sanjib Sharma , Matthias Steinmetz

A halo model is presented which possesses a constant phase space density (Q) core followed by a radial CDM-like power law decrease in Q. The motivation for the core is the allowance for a possible primordial phase space density limit such…

Astrophysics · Physics 2009-11-13 F. D. A. Hartwick

We use dissipationless N-body simulations to investigate the evolution of the true coarse-grained phase-space density distribution f(x,v) in equal-mass mergers between dark matter (DM) halos. The halo models are constructed with various…

Astrophysics · Physics 2011-02-11 Ileana M. Vass , Stelios Kazantzidis , Monica Valluri , Andrey V. Kravtsov

We study the use of parallax microlensing to separate the effects of the mass function of dark massive halo objects (MHOs or `machos') on the one hand and their spatial distribution and kinematics on the other. This disentanglement is…

Astrophysics · Physics 2007-05-23 D. Markovic

The cooling of gas in the centers of dark matter halos is expected to lead to a more concentrated dark matter distribution. The response of dark matter to the condensation of baryons is usually calculated using the model of adiabatic…

Astrophysics · Physics 2011-05-05 Oleg Y. Gnedin , Andrey V. Kravtsov , Anatoly A. Klypin , Daisuke Nagai

N-body simulations suggest that the substructures that survive inside dark matter haloes follow universal distributions in mass and radial number density. We demonstrate that a simple analytical model can explain these subhalo distributions…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-17 Jiaxin Han , Shaun Cole , Carlos S. Frenk , Yipeng Jing

$N$-body cosmological simulations are an essential tool to understand the observed distribution of galaxies. We use the MultiDark simulation suite, run with the Planck cosmological parameters, to revisit the mass and velocity functions. At…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-16 Johan Comparat , Francisco Prada , Gustavo Yepes , Anatoly Klypin