Dark Energy and Dark Matter in Galaxy Halos

Abstract

We consider the possibility that the dark matter is coupled through its mass to a scalar field associated with the dark energy of the Universe. In order for such a field to play a role at the present cosmological distances, it must be effectively massless at galactic length scales. We discuss the effects of the field on the distribution of dark matter in galaxy halos. We show that the profile of the distribution outside the galaxy core remains largely unaffected and the approximately flat rotation curves persist. The dispersion of the dark matter velocity is enhanced by a potentially large factor relative to the case of zero coupling between dark energy and dark matter. The counting rates in terrestrial dark matter detectors are similarly enhanced. Existing bounds on the properties of dark matter candidates can be extended to the coupled case, by taking into account the enhancement factor.

arXiv comment7 pages, 1 figure, references added and discussion expanded

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Cited by in corpus (7)

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• Observational constraints on the dark energy and dark matter mutual coupling
• Probing Dark Energy at Galactic and Cluster Scales
• A preliminary analysis of the energy transfer between the dark sectors of the Universe
• Neutrino Lumps in Quintessence Cosmology
• Direct Detection Rates of Dark Matter Coupled to Dark Energy