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We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06<z<0.7. The observed dark matter and total mass (dark-plus-luminous matter) profiles can…

Astrophysics · Physics 2008-11-26 R. W. Schmidt , S. W. Allen

Based on the Millennium Simulation we examine assembly bias for the halo properties: shape, triaxiality, concentration, spin, shape of the velocity ellipsoid and velocity anisotropy. For consistency we determine all these properties using…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Andreas Faltenbacher , Simon D. M. White

Simple self-consistent models of galaxy groups and clusters are tested against the results of high-resolution adiabatic gasdynamical simulations. We investigate two models based on the existence of a 'universal' dark matter density profile…

Astrophysics · Physics 2009-11-07 Y. Ascasibar , G. Yepes , V. Mueller , S. Gottloeber

High resolution N-body simulations show that the density profiles of dark matter halos formed in the standard CDM cosmogony can be fit accurately by scaling a simple ``universal'' profile. Regardless of their mass, halos are nearly…

Astrophysics · Physics 2007-05-23 Julio F. Navarro

We study the cosmic velocity-density relation using the spherical collapse model (SCM) as a proxy to non-linear dynamics. Although the dependence of this relation on cosmological parameters is known to be weak, we retain the density…

Astrophysics · Physics 2013-11-22 Maciej Bilicki , Michał Chodorowski

Using a sample of 100 H I - selected damped Lyman alpha (DLA) systems, observed with the High Resolution Echelle Spectrometer on the Keck I telescope, we present evidence that the scatter in the well-studied correlation between the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-07 Marcel Neeleman , Arthur M. Wolfe , J. Xavier Prochaska , Marc Rafelski

We carry out fully 3-dimensional simulations of evolution from self-similar, spherically symmetric linear perturbations of a Cold Dark Matter dominated Einstein-de Sitter universe. As a result of the radial orbit instability, the haloes…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Mark Vogelsberger , Roya Mohayaee , Simon D. M. White

The nature of dark matter is increasingly constrained by cosmological data. In this paper, we examine the implications of the Cosmic Microwave Background anisotropy limits on the density of cold dark matter under different theoretical…

Astrophysics · Physics 2009-11-07 A. Melchiorri , J. Silk

We present Halpha rotation curves for a sample of 15 dwarf and LSB galaxies. From these, we derive limits on the slopes of the central mass distributions. Assuming the density distributions of dark matter halos follow a power-law at small…

Astrophysics · Physics 2008-11-26 R. A. Swaters , B. F. Madore , F. C. van den Bosch , M. Balcells

We have made a likelihood statistical analysis of the angular correlations in the {\it COBE}-DMR two-year sky maps by Monte Carlo simulation of the temperature fluctuations. We assume an open universe and consider as primordial power…

Astrophysics · Physics 2015-06-24 L. Cayon , E. Martinez-Gonzalez , J. L. Sanz , N. Sugiyama , S. Torres

High-resolution N--body simulations show a remarkable similarity in the structure of dark matter halos formed through dissipationless hierarchical clustering. Independent of halo mass, power spectrum, and cosmological parameters, the…

Astrophysics · Physics 2008-02-03 Julio F. Navarro

Using a sample of ten nearby (z< 0.15), relaxed galaxy clusters in the temperature range [2-9] keV, we have investigated the scaling relation between the mass at various density contrasts (delta=2500,1000,500,200) and the cluster…

Astrophysics · Physics 2008-11-26 M. Arnaud , E. Pointecouteau , G. W. Pratt

We investigate the structure of the dark matter halo formed in the cold dark matter scenario using $N$-body simulations. We simulated 12 halos with the mass of $6.6\times 10^{11}M_{\odot}$ to $8.0\times 10^{14}M_{\odot}$. In almost all…

Astrophysics · Physics 2008-11-26 Toshiyuki Fukushige , Junichiro Makino

Dark matter haloes in cosmological N-body simulations are affected by processes such as mergers, accretion and the gravitational interaction with baryonic matter. Typically the analysis of dark matter haloes is performed in spherical or…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-26 Martin Sparre , Steen H. Hansen

Properties of dark matter halos are reviewed. Taken from different publications, we present results on (1) the mass and velocity functions, (2) density and velocity profiles, and (3) concentration of halos. In the range of radii…

Astrophysics · Physics 2007-05-23 Anatoly Klypin

We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low mass galaxies frequently suggest…

Dark matter haloes from cosmological N-body simulations typically have triaxial shapes and anisotropic velocity distributions. Recently it has been shown that the velocity anisotropy, beta, of cosmological haloes and major merger remnants…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-13 Martin Sparre , Steen H. Hansen

We give a summary of our recent studies of spatial and velocity biases of galaxy-size halos in cosmological models. Recent progress in numerical techniques made it possible to simulate halos in large volumes with a such accuracy that halos…

Astrophysics · Physics 2007-05-23 Anatoly Klypin , Andrey V. Kravtsov , Pedro Colin

We used our database of ESO VLT-UVES spectra of quasars to build up a sample of 67 Damped Lyman-alpha (DLA) systems with redshifts 1.7<zabs<3.7. For each system, we measured average metallicities relative to Solar, [X/H] (with either X=Zn,…

Astrophysics · Physics 2009-11-11 C. Ledoux , P. Petitjean , P. Moller , J. Fynbo , R. Srianand

Galaxies show different halo scaling relations such as the Radial Acceleration Relation, the Mass Discrepancy Acceleration Relation (MDAR) or the dark matter Surface Density Relation (SDR). At difference with traditional studies using…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 A. Krut , C. R. Argüelles , P. -H. Chavanis , J. A. Rueda , R. Ruffini