http://arxiv.org/abs/2006.12320
A large number of studies have found that the dark matter surface density, given by the product of the dark matter core radius ($r_c$) and core density ($\rho_c$) is approximately constant for a wide range of galaxy systems. However, there has been only one systematic study of this {\it ansatz} for galaxy clusters by Chan (arXiv:1403.4352), who found that the surface density for clusters is not constant and $\rho_c \sim r_c^{-1.46}$. We implement a test of this {\it ansatz} for an X-ray sample of 12 relaxed clusters from Chandra observations, studied by Vikhlinin et al (astro-ph/0507092), implementing the same procedure as in arXiv:1403.4352, but also accounting for the gas and star mass. We find that $\rho_c \propto r_c^{-1.08 \pm 0.055}$, with an intrinsic scatter of about 18%. Therefore, we get a much shallower slope for the relation between core density and radius as compared to previous estimates, and the dark matter surface density shows deviations from a constant value at only about 1.4$\sigma$.
G. K. and S. Desai
Tue, 23 Jun 20
63/84
Comments: 9 pages, 2 figues
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