Speaker
Description
AGN feedback has become a standard ingredient in cosmological simulations to help regulate the development of cooling flows and star formation from the scales of galaxies to groups and clusters. However, it is difficult to fine-tune the feedback efficiency to reproduce the observed cool-core fractions at all scales. In the paper "How the cool-core population transitions from galaxy groups to massive clusters", we show that although a constant canonical feedback efficiency of ~0.10 in radio mode works at the scale of massive clusters, it results in an excess of AGN feedback at the scale of groups, suppressing the mid- and strong-cool-core populations in comparison with observations. To address this problem, we present a new model for the AGN efficiency in radio mode, based on the relative strength between the gravitational force and the Lorentz force driven by magnetic fields at the event horizon, which results in a feedback efficiency directly proportional to the accretion rate and scales well from the scales of galaxy groups up to clusters.