Scaling relations for dark matter core density and radius from Chandra X-ray cluster sample

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 ansatz for galaxy clusters by Chan et al. (2015), who found that the surface density for clusters is not constant and rho(c) similar to r(c)(-1.46). We carry out this test for an X-ray sample of 12 relaxed clusters from Chandra observations, studied by Vikhlinin et al. (2006), implementing the same procedure as in Ref. Chan et al. (2015), but also accounting for the gas and star mass. We find that rho(c) proportional to r(c)(-1.08 +/- 0.055), with an intrinsic scatter of about 18%. Therefore, the dark matter surface density for our cluster data shows deviations from a constant value at only about 1.4 sigma. (c) 2020 Elsevier B.V. All rights reserved.