Self-regulated growth of supermassive black holes by a dual jet-heating active galactic nucleus feedback mechanism: methods, tests and implications for cosmological simulations

Abstract

We develop a subgrid model for the growth of supermassive black holes (BHs) and their associated active galactic nucleus (AGN) feedback in hydrodynamical cosmological simulations. This model transposes previous attempts to describe BH accretion and AGN feedback with the smoothed particle hydrodynamics (SPH) technique to the adaptive mesh refinement framework. It also furthers their development by implementing a new jet‐like outflow treatment of the AGN feedback which we combine with the heating mode traditionally used in the SPH approach. Thus, our approach allows one to test the robustness of the conclusions derived from simulating the impact of self‐regulated AGN feedback on galaxy formation vis‐à‐vis the numerical method. Assuming that BHs are created in the early stages of galaxy formation, they grow by mergers and accretion of gas at a Eddington‐limited Bondi accretion rate. However this growth is regulated by AGN feedback which we model using two different modes: a quasar‐heating mode when accretion rates on to the BHs are comparable to the Eddington rate, and a radio‐jet mode at lower accretion rates which not only deposits energy, but also deposits mass and momentum on the grid. In other words, our feedback model deposits energy as a succession of thermal bursts and jet outflows depending on the properties of the gas surrounding the BHs. We assess the plausibility of such a model by comparing our results to observational measurements of the co‐evolution of BHs and their host galaxy properties, and check their robustness with respect to numerical resolution. We show that AGN feedback must be a crucial physical ingredient for the formation of massive galaxies as it appears to be able to efficiently prevent the accumulation of and/or expel cold gas out of haloes/galaxies and significantly suppress star formation. Our model predicts that the relationship between BHs and their host galaxy mass evolves as a function of redshift, because of the vigorous accretion of cold material in the early Universe that drives Eddington‐limited accretion on to BHs. Quasar activity is also enhanced at high redshift. However, as structures grow in mass and lose their cold material through star formation and efficient BH feedback ejection, the AGN activity in the low‐redshift Universe becomes more and more dominated by the radio mode, which powers jets through the hot circumgalactic medium.

The rise and fall of stellar across the peak of cosmic star formation history: effects of mergers versus diffuse stellar mass acquisition

“…The simulation also follow the formation of black holes (BHs), which can grow by gas accretion at a Bondi-capped-at-Eddington rate and coalesce when they form a tight enough binary. BHs release energy in a quasar/radio (heating/jet) mode when the accretion rate is respectively above and below one per cent of Eddington, with efficiencies tuned to match the BH-galaxy scaling relations at z = 0 (see Dubois et al 2012b, for details).…”

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

“…Thermal or kinetic AGN feedback is often thought to heat and expel most residual gas from the galaxy (e.g. Springel et al 2005;Croton et al 2006;Bower et al 2008;Dubois et al 2012), reducing the SFR. On the contrary, our results suggest an entirely opposite effect, indicating the formation of an additional population of stars, compared to the RQQs.…”

Density profile of dark matter haloes and galaxies in the horizon–agn simulation: the impact of AGN feedback

“…They also release energy in a quasar (heating) or radio (kinetic jet) mode when the accretion rate is above (below) one per cent of Eddington, with efficiencies tuned to match the BH-galaxy scaling relations (see Dubois et al 2012 for detail). The presence of both quasar and radio modes is supported by recent observations.…”