Metal enrichment processes.pdfVIP

a r X i v : 0 8 0 1 .1 0 6 1 v 1 [ a s t r o - p h ] 7 J a n 2 0 0 8 SSRv manuscript No. (will be inserted by the editor) Metal enrichment processes S. Schindler · A. Diaferio Received: 12 November 2007 ; Accepted: 7 December 2007 Abstract There are many processes that can transport gas from the galaxies to their environment and enrich the environment in this way with metals. These metal enrich- ment processes have a large influence on the evolution of both the galaxies and their environment. Various processes can contribute to the gas transfer: ram-pressure strip- ping, galactic winds, AGN outflows, galaxy-galaxy interactions and others. We review their observational evidence, corresponding simulations, their efficiencies, and their time scales as far as they are known to date. It seems that all processes can contribute to the enrichment. There is not a single process that always dominates the enrichment, because the efficiencies of the processes vary strongly with galaxy and environmental properties. Keywords galaxies: clusters: general, ISM: jets and outflows, galaxies: ISM, galaxies: interaction 1 Introduction The gas between the galaxies in a cluster - the Intra-Cluster Medium (ICM) - does not only contain primordial elements, but also a considerable amount of heavy ele- ments like Fe, Si, S, or O (see Werner et al. 2008 - Chapter 16, this volume) resulting in metallicities around 0.5 in Solar units and sometimes even higher values. A large fraction (≈ 15?20 %) of the total mass of a cluster is in the ICM, whereas the galaxies contribute a substantially smaller fraction (3 ? 5 %), and the rest is dark matter. It follows that there is more mass in metals in the ICM than in all the galaxies of a S. Schindler Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25, 6020 Inns- bruck, Austria E-mail: Sabine.Schindler@uibk.ac.at A. Diaferio Dipartimento di Fisica Generale “Amedeo Avogadro”, Universita? degli Studi di Torino, Via P