2005/09/30 by N. Brouzakis, N Brouzakis, N. Tetradis +1
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Pulsars and Gravitational Waves Research #astro-ph #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2006/01/004
published as JCAP 0601:004,2006 · 23 pages, 3 figures, minor additions to the text
arxiv created 2005/12/08 · openalex publication_date 2006/01/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas–Fermi approximation. The mass of the dark matter particles is a function of the scalar field. We analyse the profile of the dark matter haloes in galaxies. In this case our framework is equivalent to the model of the isothermal sphere. In the presence of a scalar field, the velocity of a massive object orbiting the galaxy is not of the order of the typical velocity of the dark matter particles, as in the conventional picture. Instead, it is reduced by a factor that quantifies the dependence of the dark matter mass on the scalar field. This has implications for dark matter searches. We derive new solutions of the Einstein equations which describe compact objects composed of dark matter. Depending on the scale of the dark matter mass, the size of these objects can vary between microscopic scales and cosmological distances. We determine the mass to radius relation and discuss similarities with conventional neutron stars and exotic astrophysical objects.