Radiative and Momentum-Based Mechanical Active Galactic Nucleus Feedback in a Three-Dimensional Galaxy Evolution Code

Abstract

We study the growth of black holes (BHs) in galaxies using three-dimensional smoothed particle hydrodynamic simulations with new implementations of the momentum mechanical feedback, and restriction of accreted elements to those that are gravitationally bound to the BH. We also include the feedback from the X-ray radiation emitted by the BH, which heats the surrounding gas in the host galaxies, and adds radial momentum to the fluid. We perform simulations of isolated galaxies and merging galaxies and test various feedback models with the new treatment of the Bondi radius criterion. We find that overall the BH growth is similar to what has been obtained by earlier workers using the Springel, Di Matteo, & Hernquist algorithms. However, the outflowing wind velocities and mechanical energy emitted by winds are considerably higher (v w ∼ 1000 − 3000 km s −1 ) compared to the standard thermal feedback model (v w ∼ 50 − 100 km s −1 ). While the thermal feedback model emits only 0.1% of BH released energy in winds, the momentum feedback model emits more than 30% of the total energy released by the BH in winds. In the momentum feedback model, the degree of fluctuation in both radiant and wind output is considerably larger than in the standard treatments. We check that the new model of the BH mass accretion agrees with analytic results for the standard Bondi problem.

Do we expect most AGN to live in discs?

“…We stress that the relation and scatter are well-anchored at z = 0, but increasingly uncertain at high redshifts. But theoretical models give similar redshift evolution, mostly owing to the more gas-rich, compact nature of high-redshift hosts (see Hopkins et al 2007a;Johansson et al 2009;Choi et al 2012). In any case, the results of varying the assumed redshift evolution are shown in Paper II (Figs.…”

“…However, the Paper I model remains a good description of some observations at z = 0, and captures many of the key processes from simulations which appear to be robust even as resolution and the treatment of AGN, star formation, feedback, and ISM physics has improved (see the comparisons in Debuhr et al 2010Debuhr et al , 2012Johansson et al 2009;Choi et al 2012). We therefore, in this paper, re-visit these models for AGN fueling, but attempt to incorporate them into a modern, and observationally-constrained "population synthesis" model.…”

A Global Three-Dimensional Radiation Magneto-Hydrodynamic Simulation of Super-Eddington Accretion Disks

“…This not only allows for rapid black hole growth, but also implies that there may be significant levels of both radiative and mechanical AGN feedback. Such feedback may play a critical role in the growth of black holes in the early universe and the evolution of the host galaxies (Ciotti & Ostriker 2007;Ciotti et al 2010;Choi et al 2012). …”

Star formation in mergers with cosmologically motivated initial conditions

“…Feedback from accretion supermassive black holes can have an important effect in regulating SF during mergers (Di Hopkins et al 2006;Choi et al 2012). During mergers, gas can be efficiently funnelled towards the center of the galaxy triggering rapid accretion onto the BH (Quasar phase) and a subsequent substantial deposition of energy into the interstellar medium.…”