A tight scaling relation of dark matter in galaxy clusters

Recent studies in different types of galaxies reveal that the product of the central density and the core radius (ρ_cr_c) is a constant. However, some empirical studies involving galaxy clusters suggest that the product ρ_cr_c depends weakly on the total dark halo mass. In this Letter, we re-analyse the hot gas data from 106 clusters and obtain a surprisingly tight scaling relation: ρ_cαr_c^-1.46±0.16c. This result generally agrees with the claims that ρ_cr_c is not a constant for all scales of structure. Moreover, this relation does not support the velocity-dependent crosssection of dark matter if the core formation is due to the self-interaction of dark matter. Copyright © 2014 The Author.