Cool Core Clusters from Cosmological Simulations
Date Issued
2015
Author(s)
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Planelles, S.
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Beck, A. M.
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Ragone-Figueroa, C.
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Steinborn, L. K.
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Dolag, K.
Description
We are greatly indebted to Volker Springel for the access to the GADGET3 code; to D. Fabjan, V. Fiorenzo, M. Petkova, and L. Tornatore for the simulation set-up; and to the referee, D. Eckert, S. Ettori, A. Evrard, M. Gaspari, S. Molendi, P. Monaco, P. Tozzi, M. Voit for useful discussions. We acknowledge financial support from PIIF-GA- 2013-627474, NSF AST-1210973, PRIN-MIUR 201278X4FL, PRIN-INAF 2012 “The Universe in a Box: Multi-scale Simulations of Cosmic Structures,” the INFN INDARK grant, “Consorzio per la Fisica” of Trieste, DFC Cluster of Excellence “Universe,” DFC Research Unit 1254, CONICET-Argentina, FonCyT. Simulations are carried out using Flux HCP Cluster at the University of Michigan, Galileo at CINECA (Italy), with CPU time assigned through ISCRA proposals and an agreement with the University of Trieste, and PICO at CINECA though our expression of interest.
Abstract
We present results obtained from a set of cosmological hydrodynamic simulations of galaxy clusters, aimed at comparing predictions with observational data on the diversity between cool-core (CC) and non-cool-core (NCC) clusters. Our simulations include the effects of stellar and active galactic nucleus (AGN) feedback and are based on an improved version of the smoothed particle hydrodynamics code GADGET-3, which ameliorates gas mixing and better captures gas-dynamical instabilities by including a suitable artificial thermal diffusion. In this Letter, we focus our analysis on the entropy profiles, the primary diagnostic we used to classify the degree of cool-coreness of clusters, and the iron profiles. In keeping with observations, our simulated clusters display a variety of behaviors in entropy profiles: they range from steadily decreasing profiles at small radii, characteristic of CC systems, to nearly flat core isentropic profiles, characteristic of NCC systems. Using observational criteria to distinguish between the two classes of objects, we find that they occur in similar proportions in both simulations and observations. Furthermore, we also find that simulated CC clusters have profiles of iron abundance that are steeper than those of NCC clusters, which is also in agreement with observational results. We show that the capability of our simulations to generate a realistic CC structure in the cluster population is due to AGN feedback and artificial thermal diffusion: their combined action allows us to naturally distribute the energy extracted from super-massive black holes and to compensate for the radiative losses of low-entropy gas with short cooling time residing in the cluster core.
Volume
813
Issue
1
Start page
L17
Issn Identifier
2041-8205
Ads BibCode
2015ApJ...813L..17R
Rights
open.access
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