A Parameter Space Exploration of Galaxy Cluster Mergers I: Gas Mixing and the Generation of Cluster Entropy - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




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Abstract: We present a high-resolution set of adiabatic binary galaxy cluster mergersimulations using FLASH. These are the highest-resolution simulations to dateof such mergers using an AMR grid-based code with Eulerian hydrodynamics. Inthis first paper in a series we investigate the effects of merging on theentropy of the hot intracluster gas, specifically with regard to the ability ofmerging to heat and disrupt cluster -cool-cores.- We find, in line with recentworks, that the effect of fluid instabilities that are well-resolved ingrid-based codes is to significantly mix the gases of the two clusters and tosignificantly increase the entropy of the gas of the final merger remnant. Thisresult is characteristic of mergers over a range of initial mass ratio andimpact parameter. In line with this, we find that the kinetic energy associatedwith random motions is higher in our merger remnants which have high entropyfloors, indicating the motions have efficiently mixed the gas and heated thecluster core with gas of initially high entropy. We examine the implications ofthis result for the maintenance of high entropy floors in the centers of galaxyclusters and the derivation of the properties of dark matter from the thermalproperties of the X-ray emitting gas.



Author: John ZuHone Harvard-Smithsonian Center for Astrophysics

Source: https://arxiv.org/







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