Thermodynamic and chemical properties of the intra-cluster medium in the outer regions of galaxy clusters

Clusters of galaxies are the most massive gravitationally bound systems in the universe. They are permeated by a hot, X-ray emitting, intra-cluster medium (ICM), which represents the dominant baryonic component. The key ICM observable quantities are its density, temperature, and chemical composition (in particular, the so-called metallicity). Measuring the gas density is relatively simple, whereas measuring the temperature and the metallicity of the ICM requires accumulating a spectrum and fitting it with a plasma model. The aim of my thesis is the characterization of the radial properties (especially temperature and metallicity) of the ICM, for a large sample of clusters of galaxies observed with XMM-Newton. Particular attention was paid to investigate and characterize the systematic effects that may affect measurements. I also employed simulations to examine how best to analyze spectra with poor statistical quality and find an unbiased estimator of the temperature (Leccardi & Molendi, 2007). Finally, I reported some preliminary results obtained by investigating thermodynamic and chemical properties of cluster cores for an enlarged sample from z = 0.02 to z = 0.25; these results will be discussed in a forthcoming paper (Leccardi et al., in prep.). The bulk of my thesis is based on two published papers, namely Leccardi & Molendi (2008a) and Leccardi & Molendi (2008b).