Inhomogeneous metal distribution in the intracluster medium

Institut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
e-mail: Lorenzo.Lovisari@uibk.ac.at

Received: 15 July 2010
Accepted: 14 January 2011

Abstract

Context. The hot gas that fills the space between galaxies in clusters is rich in metals. In their large potential wells, galaxy clusters accumulate metals over the whole cluster history and hence retain important information on cluster formation and evolution.

Aims. We use a sample of five cool core clusters to study the distribution of metals in the ICM. We investigate whether the X-ray observations yield good estimates for the metal mass and whether the heavy elements abundances are consistent with a certain relative fraction of SN Ia to SNCC.

Methods. We derived detailed metallicity maps of the clusters from XMM - Newton observations and used them as a measure for the metal mass in the ICM. We determined radial profiles for several elements, and using population synthesis and chemical enrichment models, we studied the agreement between the measured abundances and the theoretical yields.

Results. We show that the distribution of metals show a lot of inhomogeneities even in relaxed clusters. Using metal maps usually gives a metal mass 10–30% higher than the metal mass computed using a single extraction region, so it is expected that most previous metal mass determination have underestimated metal mass. The abundance ratio of α-elements to Fe, even in the central parts of clusters, are consistent with an enrichment thanks to the combination of SN Ia and SNCC.