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We study the evolution of Hernquist profile ``galaxies'' in the presence of self-interacting dark matter (SIDM), where the properties of the dark matter can be parameterized by one number, sigma-hat = sigma M/a^2 for a halo of mass M and…

Astrophysics · Physics 2009-08-18 C. S. Kochanek , Martin White

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 establish the presence of a dark matter core radius, for the first time in a very large number of spiral galaxies of all luminosities. Contrary to common opinion we find that the sizes of these cores and the " DM core problem" are bigger…

Astrophysics · Physics 2009-10-31 Paolo Salucci , Andreas Burkert

A sufficiently light scalar field slowly evolving in a potential can account for the dark energy that presently dominates the universe. This quintessence field is expected to couple directly to matter components, unless some symmetry of a…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-09 Ewan R. M. Tarrant , Carsten van de Bruck , Edmund J. Copeland , Anne M. Green

In the framework of the unimodular metagravity, with the scalar graviton/graviscalar dark matter, a regular anomalous one-parameter solution to the static spherically symmetric metagravity equations in empty space is found. The solution…

General Relativity and Quantum Cosmology · Physics 2010-10-19 Yu. F. Pirogov

Self-consistent bars that form in galaxies embedded within cuspy halos are unable to flatten the cusp. Short bars form in models with quasi-flat rotation curves. They lose angular momentum to the halo through dynamical friction, but the…

Astrophysics · Physics 2009-11-07 J. A. Sellwood

We present a model for the dark matter in spiral galaxies, which is a result of a static and axial symmetric exact solution of the Einstein-Dilaton theory. We suposse that dark matter is a scalar field endowed with a scalar potential. We…

General Relativity and Quantum Cosmology · Physics 2010-04-06 F. Siddhartha Guzman , Tonatiuh Matos

We calculate the energy that baryons must inject in cold dark matter (CDM) haloes in order to remove centrally-divergent DM cusps on scales relevant to observations of dwarf spheroidal galaxies (dSphs). We estimate that the CDM haloes often…

Astrophysics of Galaxies · Physics 2015-06-05 Jorge Peñarrubia , Andrew Pontzen , Matthew G. Walker , Sergey E. Koposov

There are several issues to do with dwarf galaxy predictions in the standard $\Lambda$CDM cosmology that have suscitated much recent debate about the possible modification of the nature of dark matter as providing a solution. We explore a…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-07 David J. E. Marsh , Joe Silk

For almost two decades the properties of "dwarf" galaxies have challenged the Cold Dark Matter (CDM) paradigm of galaxy formation. Most observed dwarf galaxies consists of a rotating stellar disc embedded in a massive DM halo with a near…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Fabio Governato , Chris Brook , Lucio Mayer , Alyson Brooks , George Rhee , James Wadsley , Patrik Jonsson , Beth Willman , Greg Stinson , Thomas Quinn , Piero Madau

Using Warm Dark Matter rather then Cold Dark Matter we are able to solve the over-production of satellite galaxies orbiting in galactic haloes. Moreover, we can show that this model leads to interesting new results in terms of the history…

Astrophysics · Physics 2007-05-23 Alexander Knebe

Recent cosmological hydrodynamical simulations suggest that baryonic processes, and in particular supernova feedback after bursts of star formation, can alter the structure of dark matter haloes and transform primordial cusps into shallower…

Astrophysics of Galaxies · Physics 2017-09-13 F. Allaert , G. Gentile , M. Baes

In this work we analyze the viability of use a particular models of scalar fields in the context of the galactic dark matter problem. These models are based on a single scalar field, minimally coupled to the gravity in a asymptotically flat…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jose A. Gonzalez , Daniel Sudarsky

Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken $U(1)'$ gauge symmetry,…

Astrophysics of Galaxies · Physics 2015-06-03 R. Foot

The disparity between the density profiles of galactic dark matter haloes predicted by dark matter only cosmological simulations and those inferred from rotation curve decomposition, the so-called cusp-core problem, suggests that baryonic…

Astrophysics of Galaxies · Physics 2015-06-19 Peter R Hague , Mark I Wilkinson

This paper reviews the available information on the central density distribution and shape of the Milky Way's halo. At present, there is no strong evidence that the Milky Way's halo properties conflict with the predictions of cold dark…

Astrophysics · Physics 2007-05-23 M. R. Merrifield

Dissipative dark matter, such as mirror dark matter and related hidden sector dark matter candidates, requires an energy source to stabilize dark matter halos in spiral galaxies. It has been proposed previously that supernovae could be the…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-09 R. Foot

We present more results from a fully cosmological LCDM simulation of a group of isolated dwarf galaxies that has been shown to reproduce the observed stellar mass and cold gas content, resolved star formation histories, and metallicities of…

Astrophysics of Galaxies · Physics 2015-06-19 Piero Madau , Sijing Shen , Fabio Governato

We investigate in detail the mass distribution obtained by means of high resolution rotation curves of 25 galaxies of different morphological types. The dark matter contribution to the circular rotation velocity is well-described by…

Astrophysics · Physics 2011-02-11 F. Donato , G. Gentile , P. Salucci

The nature of the dark matter that binds galaxies remains an open question. The favored candidate has been so far the neutralino. This massive species with evanescent interactions is now in difficulty. It would actually collapse in dense…

Astrophysics · Physics 2009-11-06 Alexandre Arbey , Julien Lesgourgues , Pierre Salati