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After deducing the density profiles and gravitational potential functions of eight galaxies from the rotation velocity data from THINGS, we find that the density decreases exponentially with the potential in substantial regions of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Joshua Davidson , Sanjoy K. Sarker , Allen Stern

We analyze the physical justification of the picture proposed by Salvador-Sole et al. in these proceedings for the time evolution of the universal density profile of dark-matter halos. According to this picture, halos have at formation a…

Astrophysics · Physics 2007-05-23 G. Gonzalez-Casado , A. Raig , E. Salvador-Sole

We investigate the intrinsic alignments of dark halo substructures with their host halo major-axis orientations both analytically and numerically. Analytically, we derive the probability density distribution of the angles between the minor…

Astrophysics · Physics 2009-11-10 Jounghun Lee , Xi Kang , Yipeng Jing

The standard cosmological model, now strongly constrained by direct observation at early epochs, is very successful in describing the structure of the evolved universe on large and intermediate scales. Unfortunately, serious contradictions…

Astrophysics · Physics 2009-11-11 Sergey Mashchenko , H. M. P. Couchman , James Wadsley

The shapes of individual self-gravitating structures of an ensemble of identical, collisionless particles have remained elusive for decades. In particular, a reason why mass density profiles like the Navarro-Frenk-White or the Einasto…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Jenny Wagner

We present a model that builds ``dark matter"-like halo density profiles from free-falling zero-point vacuum fluctuations. It does not require a modification of Newton's laws, nor the existence of as-yet-undiscovered dark matter particles.…

General Relativity and Quantum Cosmology · Physics 2023-02-06 François Couchot , Arache Djannati-Ataï , Scott Robertson , Xavier Sarazin , Marcel Urban

We study the evolution of the halo-halo correlation function and bias in four cosmological models (LCDM, OCDM, tauCDM, and SCDM) using very high-resolution N-body simulations. The high force and mass resolution allows dark matter (DM) halos…

Astrophysics · Physics 2009-10-30 Pedro Colin , Anatoly Klypin , Andrey Kravtsov , Alexei Khokhlov

We use N-body simulations of dark matter haloes in cold dark matter (CDM) and a large set of different warm dark matter (WDM) cosmologies to demonstrate that the spherically averaged density profile of dark matter haloes has a shape that…

Astrophysics of Galaxies · Physics 2015-05-20 E. Polisensky , M. Ricotti

The structural and dynamic properties of the dark matter halos, though an important ingredient in understanding large-scale structure formation, require more conservative particle resolution than those required by halo mass alone in a…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 Sujatha Ramakrishnan , Premvijay Velmani

Collisionless self-gravitating systems, e.g., cold dark matter halos, harbor universal density profiles despite the intricate non-linear physics of hierarchical structure formation, the origin of which has been a persistent mystery. To…

Astrophysics of Galaxies · Physics 2025-06-09 Uddipan Banik , Amitava Bhattacharjee

We investigate the collapse and internal structure of dark matter halos. We consider halo formation from initially scale-free perturbations, for which gravitational collapse is self-similar. Fillmore and Goldreich (1984) and Bertschinger…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-21 Yoram Lithwick , Neal Dalal

We present analysis of the evolution of dark matter halos in dense environments of groups and clusters in dissipationless cosmological simulations. The premature destruction of halos in such environments, known as the overmerging, reduces…

Astrophysics · Physics 2009-10-30 Anatoly Klypin , Stefan Gottloeber , Andrey Kravtsov , Alexei Khokhlov

The concordance cosmological model based on cold dark matter makes definitive predictions for the growth of galaxies in the Universe, which are being actively studied using numerical simulations. These predictions appear to contradict the…

Astrophysics · Physics 2015-06-24 Oleg Y. Gnedin

Galactic collisions are normally modeled in a CDM model by assuming the DM consists of a small number of very massive objects. This note shows that the behaviour of a CDM halo during collisions depends critically on the mass of the…

Astrophysics · Physics 2007-05-23 Peter J. S. Watson

We calculate by means of the Press-Schechter formalism the density profile developed by dark-matter halos during accretion, i.e., the continuous aggregation of small clumps. We find that the shape of the predicted profile is similar to that…

Ultra-light dark matter (ULDM) refers to a class of theories, including ultra-light axions, in which particles with mass $m_{\psi} < 10^{-20}\, \rm{eV}$ comprise a significant fraction of the dark matter. A galactic scale de Broglie…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-28 Alexander Laroche , Daniel Gilman , Xinyu Li , Jo Bovy , Xiaolong Du

In the last time the cold dark matter (CDM) model has suggested more and more that it is not able to describe all the properties of nearby galaxies that can be observed in great detail as well as that it has some problems in the mechanism…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Juan Magaña , Tonatiuh Matos , Victor Robles , Abril Suárez

We investigate the connection between collisionless equilibria and the phase-space relation between density $\rho$ and velocity dispersion $\sigma$ found in simulations of dark matter halo formation, $F=\psd \propto r^{-\alpha}$.…

Astrophysics · Physics 2009-11-13 Eric I. Barnes , Liliya L. R. Williams , Arif Babul , Julianne J. Dalcanton

The structural evolution of substructure in cold dark matter (CDM) models is investigated combining ``low-resolution'' satellites from cosmological N-body simulations of parent halos with N=10^7 particles with high-resolution individual…

Accurate measurements of the mass distribution in galaxy and cluster halos are essential to test the cold dark matter (CDM) paradigm. The cosmological model predicts a universal shape for the density profile in all halos, independent of…

Astrophysics · Physics 2009-09-29 L. M. Voigt , A. C. Fabian