for Astrophysics, School of Physics & Astronomy, The University of Manchester, Manchester M13 9PL, U.K.
bibliography:
- 'bibliography.bib'
title: 'A parametric physical model for the intracluster medium and its use in joint SZ/X-ray analyses of galaxy clusters'
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methods: data analysis - galaxies: clusters: intracluster medium.

Introduction {#Introduction}
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The Sunyaev-Zel’dovich effect is a distortion of the Cosmic Microwave Background (CMB) spectrum by inverse Compton scattering off a hot population of electrons, such as in the intra-cluster medium (ICM) of a galaxy cluster [@Sunyaev:1970; @Birkinshaw:1999]. The SZ effect is observable as an anisotropy in the CMB and has a surface brightness that is proportional to the line-of-sight integral of the gas pressure of the cluster, independent of redshift. Since the surface brightness is independent of redshift, SZ observations provide a powerful tool to probe the properties of the largest virialised structures in the Universe. Over the past decade there has been considerable observational data gathered on the ICM properties of clusters via the SZ effect [e.g. @Grego:2001; @LaRoque:2006] and we are now entering an era of deep cluster surveys with specifically designed SZ telescopes, including the South Pole Telescope [SPT, @Ruhl:2004], the Sunyaev-Zel’dovich Array [SZA, @Muchovej:2007], the Atacama Cosmology 