Journal Article

2D Magnetohydrodynamics simulations of induced plasma dynamics in the near-core region of a galaxy cluster

I. G. Mikellides, K. Tassis and H. W. Yorke

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 410, issue 4, pages 2602-2616
Published in print February 2011 | ISSN: 0035-8711
Published online January 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.17635.x
2D Magnetohydrodynamics simulations of induced plasma dynamics in the near-core region of a galaxy cluster

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The mechanisms that maintain thermal balance in the intracluster medium (ICM) and produce the observed spatial distribution of the plasma density and temperature in galaxy clusters remain a subject of debate. We present results from numerical simulations of the cooling-core cluster A2199 produced by the 2D resistive magnetohydrodynamics (MHD) code mach2. In our simulations we explore the effect of anisotropic thermal conduction on the energy balance of the system. The results from idealized cases in 2D axisymmetric geometry underscore the importance of the initial plasma density in ICM simulations, especially the near-core values since the radiation cooling rate is proportional to ne2. Heat conduction is found to be non-effective in preventing catastrophic cooling in this cluster. In addition we performed 2D planar MHD simulations starting from initial conditions deliberately violating both thermal balance and hydrostatic equilibrium in the ICM, to assess contributions of the convective terms in the energy balance of the system against anisotropic thermal conduction. We find that in this case work done by the pressure on the plasma can dominate the early evolution of the internal energy over anisotropic thermal conduction in the presence of subsonic flows, thereby reducing the impact of the magnetic field. Deviations from hydrostatic equilibrium near the cluster core may be associated with transient activity of a central active galactic nucleus and/or remnant dynamical activity in the ICM and warrant further study in three dimensions.

Keywords: MHD; galaxies: clusters: intracluster medium

Journal Article.  10782 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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