Gas thermodynamics from the SZ effects

Abstract

The thermodynamic properties of the ionised baryons in galaxies, groups, and clusters encode the effects of the assembly history and feedback processes that shape galaxy and cluster formation. These properties can be studied through the thermal and kinematic Sunyaev-Zel’dovich (SZ) effects imprinted on cosmic microwave background maps, measured for individual clusters or from stacking analyses. I present SZ cross-correlation measurements from ACT and Planck , with high signal-to-noise measurements of the electron density, temperature and pressure distribution around a sample of galaxy groups. I discuss the impact of the modelling uncertainties and I present our constraints of the baryonic processes like the feedback and the non-thermal pressure support, as well as the effect of including baryons in the modelling of galaxy-galaxy lensing measurements. These measurements provide novel tests of hydrodynamical simulations with sub-grid physics models. I finally outline the rapid growth of SZ cross-correlation measurements expected over the next decade.