TAPIR Seminar

In person: 370 Cahill. To Join via Zoom: 851 0756 7442

Abstract: Simulating black hole (BH) accretion and feedback from the horizon to galactic scales is extremely challenging, as it involves a vast range of scales. Recently, our multizone method has successfully achieved global dynamical steady-states of hot accretion flows in three-dimensional general relativistic magnetohydrodynamic (GRMHD) simulations by tracking the bidirectional interaction between a non-spinning BH and its host galaxy. In this talk, we present technical improvements to the method and apply it to spin a=0.9 BHs, which power relativistic jets. We simulate strongly magnetized Bondi accretion for various Bondi radii, RB ≈ 400, 2e3, 2e4, 2e5 rg. We find that the BH accretion rate is suppressed with respect to the Bondi rate, depending on the Bondi radius RB. However, despite some variability, the time-averaged feedback efficiency is η∼30%, independent of RB. This suggests that BH feedback efficiency in hot accretion flows is mainly governed by the BH spin (a) rather than by the galactic properties (RB). From these first-principles simulations, we provide a feedback subgrid prescription for cosmological simulations.