The Self‐Regulated Growth of Supermassive Black Holes

Abstract

We present a series of simulations of the self-regulated growth of supermassive black holes (SMBHs) in galaxies via three different fueling mechanisms: major mergers, minor mergers, and disk instabilities. The SMBHs in all three scenarios follow the same black hole fundamental plane (BHFP) and correlation with bulge binding energy seen in simulations of major mergers, and observed locally. Furthermore, provided that the total gas supply is significantly larger than the mass of the SMBH, its limiting mass is not influenced by the amount of gas available or the efficiency of black hole growth. This supports the assertion that SMBHs accrete until they reach a critical mass at which feedback is sufficient to unbind the gas locally, terminating the inflow and stalling further growth. At the same time, while minor and major mergers follow the same projected correlations (e.g., the M BH -and Magorrian relations), SMBHs grown via disk instabilities do not, owing to structural differences between the host bulges. This finding is supported by recent observations of SMBHs in pseudobulges and bulges in barred systems, as compared to those hosted by classical bulges. Taken together, this provides support for the BHFP and binding energy correlations as being more ''fundamental'' than other proposed correlations in that they reflect the physical mechanism driving the coevolution of SMBHs and spheroids.

Dissipation and the Fundamental Plane: Observational Tests

“…The mass ratios we study are appropriate for the observations of ellipticals used in this paper, which are only formed in our simulations in major merger events. At higher mass ratios, the result is a small bulge in a still disk-dominated galaxy (see, e.g., Younger et al 2008;Hopkins et al 2008c, which we do not study here (although in general our conclusions should still apply, so long as the bulges of interest are ''classical'' bulges formed in mergers).…”

The Radical Consequences of Realistic Satellite Orbits for the Heating and Implied Merger Histories of Galactic Disks

“…They model the primary halo as adiabatically contracted, and merge it with either bulge + halo or disk + halo satellite models of mass ratio 1 : 5, on varying orbits with a moderately radial impact parameter. Younger et al (2008) consider full hydrodynamic merger simulations of two bulge + disk + halo systems, with mass ratios 1 : 8, 1 : 4, 1 : 3, and 1 : 2. In each case, the orbital inclination is surveyed, and two sets of models are run: one with a relatively low gas fraction $0.2 in the disk at the time of the merger (corresponding to Milky Way like disks over the last few Gyr) and one with intermediate gas fractions $0.4 (corresponding better to intermediate redshift z k1 cases).…”

Herschel Observed Stripe 82 Quasars and Their Host Galaxies: Connections Between Agn Activity and Host Galaxy Star Formation

“…SMBHs in low-and moderate-luminosity AGNs are believed to be fueled by secular processes (e.g., Hopkins et al 2006;Jogee 2006;Younger et al 2008). Many studies focused on these AGNs, yet no strong correlations between AGN luminosity and SFR (or IR luminosity) were found.…”