|
Description
A reconstruction of the total mass (the fraction of dark matter, intercluster gas, and the brightest galaxy of the cluster) of 128 X-ray galaxy clusters at redshifts 0.01-1.4 based on Chandra observations is presented. The total mass M200 and the baryonic mass Mb have been measured for all the sample objects, as well as the concentration parameter c200, which characterizes the size of the dark matter halo. The existence of a tight correlation between c200 and M200 is confirmed, c{prop.to}M^a^_vir_/(1+z)b with a=-0.56+/-0.15 and b=0.80+/-0.25 (95% confidence level), in good agreement with the predictions of numerical simulations and previous observations. Fitting the inner dark-matter density slope {alpha} with a generalized NFW model yields {alpha}=1.10+/-0.48 at the 2{sigma} confidence level, combining the results for the entire sample, for which the model gives a good description of the data. There is also a tight correlation between the inner slope of the dark-matter density profile {alpha} and the baryonic mass contentMb for massive galaxy clusters, namely, {alpha} decreases with increasing baryonic mass content. A simple power-law model is used to fit the {alpha}-M_b_ distributions, yielding the break point for the inner slope of the dark-matter density profile b=1.72+/-0.37 (68% confidence level).
|
