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The intra-cluster gas has metallicities of about one third of the solar value, i.e. at least part of the gas must have been processed in the cluster galaxies and subsequently transported from the galaxy potential wells into the potential well of the cluster.

Possible transport processes are

• galactic winds (driven by supernovae)
• ram-pressure stripping
• interaction between individual cluster galaxies

The amount of metals in the intra-cluster gas is not negligible, as it is of the same order of magnitude as all the observable metals in the cluster galaxies. The modern X-ray satellites are measuring the spatial distribution of metals within a cluster as well as the evolution of the metals with redshift.

In order to draw conclusions from these measurements about the transport mechanisms as well as the evolution of galaxies and clusters a comparison with detailed simulations is required. Such simulations have to include all components of a galaxy cluster - dark-matter, hot plasma, recepies for star formation, cooling and heating mechanisms and magentic fields.



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Ram-pressure stripping is very efficient in the dense environment in galaxy clusters. In numerical simulations we were able to show, that ram-pressures stripping can enhance the star formation rate of galaxies by a factor of three (Kronberger et al. 2008) and that off-disk star formation can occur (Kapferer et al. 2008). The simulation includes radiative cooling and a model for star formation with feedback (Springel & Hernquist, 2003).



Credits: HST

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Interacting galaxies can redistribute gaseous and stellar matter up to several 100 kpc. This leads to a direct enrichment of the intra-clustedr medium within galaxy clusters (e.g. Kapferer et al. 2005).


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The red filamentary features extending perpendicular to the galaxy are due to ionized hydrogen gas emitting its characteristic red light (the so-called "H alpha" line) at a wavelength of 6563 Angstroms. The filaments extend for over 10,000 light years in each direction from the center of the galaxy. Galactic Winds are one of the main enrichment processes in the intra-cluster medium (e.g. Kapferer et al. 2006,2007).


credits: Josef Stöckl, Wolfgang Kapferer

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A precise treatment of the intra-cluster medium is very important in all the investigations. As the intra-cluster medium is a hot plasma, magentic fields play a role in the dynamics and energetics of this plasma. In this simulation image above, the magnetic fields in the central 2 Mpc of a galaxy cluster are shown as stream lines with the temperature of the intra-cluster medium colour-coded.