ON the NATURE of HYDROSTATIC EQUILIBRIUM in GALAXY CLUSTERS
| Autor: | Giuseppe Murante, Gian Luigi Granato, Alexander M. Beck, Veronica Biffi, Klaus Dolag, Cinthia Ragone-Figueroa, Elena Rasia, Susana Planelles, Stefano Borgani, Massimo Gaspari |
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| Přispěvatelé: | ITA, Biffi, Veronica, Borgani, Stefano, Murante, G., Rasia, E., Planelles, S., Granato, G. L., Ragone Figueroa, C., Beck, A. M., Gaspari, M., Dolag, K. |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Active galactic nucleus galaxies: clusters: intracluster medium FOS: Physical sciences 01 natural sciences Virial theorem law.invention methods: numerical Gravitation law Intracluster medium 0103 physical sciences Cluster (physics) clusters: general [galaxies] 010303 astronomy & astrophysics Galaxy cluster Physics 010308 nuclear & particles physics numerical [methods] Astronomy and Astrophysics Radius Astronomy and Astrophysic Computational physics clusters: intracluster medium [galaxies] galaxies: clusters: general Space and Planetary Science Hydrostatic equilibrium Astrophysics - Cosmology and Nongalactic Astrophysics |
| Popis: | In this paper we investigate the level of hydrostatic equilibrium (HE) in the intra-cluster medium of simulated galaxy clusters, extracted from state-of-the-art cosmological hydrodynamical simulations performed with the Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several physical processes, among which stellar and AGN feedback, and have been performed with an improved version of the code that allows for a better description of hydrodynamical instabilities and gas mixing processes. Evaluating the radial balance between the gravitational and hydrodynamical forces, via the gas accelerations generated, we effectively examine the level of HE in every object of the sample, its dependence on the radial distance from the center and on the classification of the cluster in terms of either cool-coreness or dynamical state. We find an average deviation of 10-20% out to the virial radius, with no evident distinction between cool-core and non-cool-core clusters. Instead, we observe a clear separation between regular and disturbed systems, with a more significant deviation from HE for the disturbed objects. The investigation of the bias between the hydrostatic estimate and the total gravitating mass indicates that, on average, this traces very well the deviation from HE, even though individual cases show a more complex picture. Typically, in the radial ranges where mass bias and deviation from HE are substantially different, the gas is characterized by a significant amount of random motions (>~30 per cent), relative to thermal ones. As a general result, the HE-deviation and mass bias, at given interesting distance from the cluster center, are not very sensitive to the temperature inhomogeneities in the gas. 14 pages, 13 figures, 1 table; submitted |
| Databáze: | OpenAIRE |
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