Toward Multi-scale Modeling of AGN Feedback in Galaxy Clusters

Galaxy clusters are powerful cosmological probes, currently limited by the poorly understood physics of the intracluster medium (ICM) in the cluster cores where AGN feedback physics dominates. It is especially challenging to model AGN feedback physics in cosmological simulations of cluster formation due to the wide range of of the physical scales involved. We show that this challenge can be overcome by a multi-scale approach. In particular, using both idealized and cosmological simulations, we show that mergers of galaxy clusters play an important role in setting the thermodynamics in cluster cores. We also show that by incorporating the non-thermal component of the ICM, the ICM can be described by a ''universal'' equation of state independent of baryonic physics. We provide implications for these results on the understanding and the modeling of the physics of galaxy cluster cores, as well as implications for upcoming cosmological X-ray cluster surveys such as eROSITA.