Thanks to the high resolution observations of the cosmic microwave background by ACT and SPT the ability to use the Sunyaev-Zel'dovich (SZ) angular power spectrum as a probe of cosmological parameters is now limited by its theoretical uncertainties. The dominate uncertainty is a accurate model for the intracluster medium from the cluster core to beyond the virial radius. We have explored how radiative cooling, supernova feedback, cosmic rays and a new model of the energetic feedback from AGN affect this intracluster gas using a large set of hydrodynamical TreePM-SPH simulations of the cosmic web in big periodic boxes. I will discuss the average thermodynamic properties of the intracluster medium and summarize the state of the theoretical SZ power spectra templates.
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