Correlations in Relaxed Clusters of Galaxies

[摘要] The correlations among different quantities in galaxy clusters, observed by Newman et al. (2013a,b), are investigated. We find an anti-correlation among the slope α , the effective radius, R e , and a correlation among the core radius r core and R e. Moreover, the mass inside 100 kpc (mainly dark matter) is correlated with the mass inside 5 kpc (mainly baryons). The listed correlations can be understood in a two phase formation model: the first dissipative phase forming the brightest cluster galaxies, and the second dissipationless phase, in which the inner density profile is flattened by the interaction of baryonic clumps and the dark matter halo through dynamical friction.

[关键词] cosmology theory;large-scale structure of Universe;dark matter;galaxies clusters;formation