Breaking the mass / anisotropy degeneracy in the Coma cluster

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dc.creatorMamon, Gary A.
dc.creatorLokas, Ewa L.
dc.creatorSanchis, Teresa
dc.date2004-04-21
dc.date.accessioned2026-07-07T02:12:57Z
dc.date.available2026-07-07T02:12:57Z
dc.descriptionWe provide the first direct lifting of the mass/anisotropy degeneracy for a cluster of galaxies, by jointly fitting the line of sight velocity dispersion and kurtosis profiles of the Coma cluster, assuming an NFW tracer density profile, a generalized-NFW dark matter profile and a constant anisotropy profile. We find that the orbits in Coma must be quasi-isotropic, and find a mass consistent with previous analyses, but a concentration parameter 50% higher than expected in cosmological N-body simulations. We then test the accuracy of our method on realistic non-spherical systems with substructure and streaming motions, by applying it to the ten most massive structures in a cosmological N-body simulation. We find that our method yields fairly accurate results on average (within 20%), although with a wide variation (factor 1.7 at 1 sigma) for the concentration parameter, with decreased accuracy and efficiency when the projected mean velocity is not constant with radius.
dc.description5 pages, oral presentation at IAU Colloquium 195, Outskirts of Galaxy Clusters: intense life in the suburbs, ed. A. Diaferio
dc.identifierhttps://arxiv.org/abs/astro-ph/0404415
dc.identifierhttp://arxiv.org/abs/astro-ph/0404415
dc.identifierIAU Colloq. 195 (Cambridge Univ. Press), p. 413 (2004)
dc.identifierdoi:10.1017/S1743921304000869
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/7642
dc.subjectAstrophysics
dc.titleBreaking the mass / anisotropy degeneracy in the Coma cluster
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