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Recent observations have been discovering new ultra-faint dwarf galaxies as small as $\sim20~{\rm pc}$ in half-light radius and $\sim3~{\rm km~s^{-1}}$ in line-of-sight velocity dispersion. In these galaxies, dynamical friction on a star…

Astrophysics of Galaxies · Physics 2017-03-29 Shigeki Inoue

We demonstrate the potential of Deep Learning methods for measurements of cosmological parameters from density fields, focusing on the extraction of non-Gaussian information. We consider weak lensing mass maps as our dataset. We aim for our…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Jorit Schmelzle , Aurelien Lucchi , Tomasz Kacprzak , Adam Amara , Raphael Sgier , Alexandre Réfrégier , Thomas Hofmann

Although the cusp-core controversy for dwarf galaxies is seen as a problem, I argue that the cored central profiles can be explained by flattened cusps because they suffer from conflicting measurements and poor statistics and because there…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-20 Matts Roos

We study properties of dark matter halos at high redshifts z=2-10 for a vast range of masses with the emphasis on dwarf halos with masses 10^7-10^9 Msun/h. We find that the density profiles of relaxed dwarf halos are well fitted by the NFW…

Astrophysics · Physics 2009-11-10 P. Colin , A. Klypin , O. Valenzuela , S. Gottlober

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

A fundamental prediction of the Lambda Cold Dark Matter (LCDM) cosmology is the centrally divergent cuspy density profile of dark matter haloes. Density cusps render CDM haloes resilient to tides, and protect dwarf galaxies embedded in them…

Astrophysics of Galaxies · Physics 2024-06-14 Raphaël Errani , Rodrigo Ibata , Julio F. Navarro , Jorge Peñarrubia , Matthew G. Walker

Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by…

Astrophysics · Physics 2009-11-06 Alexander Knebe , Julien Devriendt , Asim Mahmood , Joseph Silk

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 derive rotation curves for four nearby, low-mass spiral galaxies and use them to constrain the shapes of their dark matter density profiles. This analysis is based on high-resolution two-dimensional Halpha velocity fields of NGC 4605,…

Astrophysics · Physics 2008-11-26 Joshua D. Simon , Alberto D. Bolatto , Adam Leroy , Leo Blitz , Elinor L. Gates

We address the question of how well the density profile of galaxy clusters can be determined by combining strong lensing and velocity dispersion data. We use cosmological dark matter simulations of clusters to test the reliability of the…

Astrophysics · Physics 2010-12-01 M. Meneghetti , M. Bartelmann , A. Jenkins , C. Frenk

We present an analysis of the mass distribution in the region of the Galactic bulge, which leads to constraints on the total amount and distribution of Dark Matter (DM) therein. Our results -based on the dynamical measurement of the BRAVA…

Astrophysics of Galaxies · Physics 2017-04-21 Fabio Iocco , Maria Benito

Maximum disk mass models fitted to galaxy rotation curves are used to show that dark matter (DM) halos in late-type and dwarf spheroidal (dSph) galaxies satisfy well defined scaling laws. Halos in less luminous galaxies have smaller core…

Astrophysics · Physics 2007-05-23 John Kormendy , K. C. Freeman

Dwarf spheroidals are low-luminosity satellite galaxies of the Milky Way highly dominated by dark matter (DM). Therefore, they are prime targets to search for signals from dark matter annihilation using gamma-ray observations. While the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-07 Niki Klop , Fabio Zandanel , Kohei Hayashi , Shin'ichiro Ando

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…

Cosmological simulations of the $\Lambda$CDM model suggest that the dark matter halos of dwarf galaxies are denser in their center than what observational data of such galaxies imply. In this letter, we propose a novel solution to this…

High Energy Physics - Phenomenology · Physics 2018-07-18 Xiaoyong Chu , Camilo Garcia-Cely

We present a synthesis of recent photometric and kinematic data for several of the most dark-matter dominated galaxies. There is a bimodal distribution in half-light radii, with stable star clusters always being smaller than $\sim30$pc,…

We use a cosmological simulation of the Local Group to make quantitative and speculative predictions for direct detection experiments. Cold dark matter (CDM) halos form via a complex series of mergers, accretion events and violent…

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 study the central dark matter (DM) cusp evolution in cosmological galactic halos. Models with and without baryons (baryons+DM, hereafter BDM model, and pure DM, PDM model, respectively) are advanced from identical initial conditions. The…

Astrophysics · Physics 2009-11-13 Emilio Romano-Diaz , Isaac Shlosman , Yehuda Hoffman , Clayton Heller

The rotation curves of dark matter dominated dwarf galaxies are analysed. The observations show that dark matter halos represent a one-parameter family with self similar density profiles. The global halo parameters, like total mass and…

Astrophysics · Physics 2007-05-23 Andreas Burkert
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