The peculiar velocity and temperature profile of galaxy clusters

Abstract

Dynamical parameters like average velocity dispersion and temperature profile of galaxy clusters are determined using the theory of quasi-equilibrium thermodynamics. The calculated results of velocity dispersion show a good agreement between theory and simulations with the results of velocity dispersion from Abdullah et al. An adaptive mesh refinement grid-based hybrid code has been used to carry out the simulations. Our results indicate that the average velocity dispersion profile of 20 Abell galaxy clusters falls in the range of 500 - 1000 km s-1 and their temperature profile is of the order of 107 to 108 K calculated on the basis of kinetic theory. The data in the plot show a significant contribution from gravitating particles clustering together in the vicinity of the cluster center and beyond a certain region this velocity dies out and becomes dominated by the Hubble flow due to which all the galaxy clusters in an expanding universe participate in Hubble expansion. © 2014 National Astronomical Observatories of Chinese Academy of Sciences and IOP Publishing Ltd.