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Issue A&A
Volume 453, Number 1, July I 2006
Page(s) 21 - 25
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361:20065151



A&A 453, 21-25 (2006)
DOI: 10.1051/0004-6361:20065151

Dark matter density profiles: a comparison of nonextensive theory with N-body simulations

T. Kronberger1, 2, M. P. Leubner1 and E. van Kampen1

1  Institut für Astro- und Teilchenphysik, Leopold-Franzens-Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
    e-mail: Thomas.Kronberger@uibk.ac.at
2  Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

(Received 30 November 2005 / Accepted 11 March 2006 )

Abstract
Density profiles of simulated galaxy cluster-sized dark matter haloes are analysed in the context of a recently introduced nonextensive theory of dark matter and gas density distributions. Nonextensive statistics accounts for long-range interactions in gravitationally coupled systems and is derived from the fundamental concept of entropy generalization. The simulated profiles are determined down to radii of $\approx$1% of R200. The general trend of the relaxed, spherically averaged profiles is accurately reproduced by the theory. For the main free parameter $\kappa$, measuring the degree of coupling within the system, and linked to physical quantities as the heat capacity and the polytropic index of the self-gravitating ensembles, we find a value of -15. The significant advantage over empirical fitting functions is provided by the physical content of the nonextensive approach.


Key words: cosmology: theory -- cosmology: dark matter -- methods: N-body simulations -- galaxies: clusters: general



© ESO 2006


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