Mass modeling of galaxy clusters: quantifying hydrostatic bias and contribution from non-thermal pressure

Understand

Galaxy cluster mass determinations achieved using X-ray and Sunyaev-Zel'dovich data combined with the assumption of hydrostatic equilibrium are generally biased.

• The bias exists for two main reasons: non-thermal pressure forces are expected to contribute to the overall pressure balance and deviations from spherical symmetry and hydrostatic equilibrium can be present.
• In this paper, we use a sample of zoom-in hydrodynamical simulations of galaxy clusters to measure the magnitude of hydrostatic bias and the non-thermal contribution to the total pressure.
• We propose a new empirical model for non-thermal pressure based on our simulations that can be applied to observations.