The rapid growth phase of supermassive black holes. Issue 3 (11th September 2018)

• Record Type: Journal Article
• Authors: McAlpine, Stuart; Bower, Richard G; Rosario, David J; Crain, Robert A; Schaye, Joop; Theuns, Tom
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 481:Issue 3(2018)
• Page Start: 3118
• Page End: 3128
• Publication Date: 2018-09-11
• Subjects: galaxies: active -- galaxies: evolution -- galaxies: formation -- galaxies: high-redshift -- galaxies: interactions; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty2489
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We investigate the rapid growth phase of supermassive black holes (BHs) within the hydrodynamical cosmological eagle simulation. This non-linear phase of BH growth occurs within ∼ L * galaxies, embedded between two regulatory states of the galaxy host: in sub L * galaxies efficient stellar feedback regulates the gas inflow on to the galaxy and significantly reduces the growth of the central BH, while in galaxies more massive than L * efficient AGN feedback regulates the gas inflow on to the galaxy and curbs further non-linear BH growth. We find evolving critical galaxy and halo mass scales at which rapid BH growth begins. Galaxies in the low-redshift Universe transition into the rapid BH growth phase in haloes that are approximately an order of magnitude more massive than their high-redshift counterparts ( M 200 ≈10 12.4 M⊙ at $z$ ≈ 0 decreasing to M 200 ≈10 11.2 M⊙ at $z$ ≈ 6). Instead, BHs enter the rapid growth phase at a fixed critical halo virial temperature ( T vir ≈ 10 5.6 K). We additionally show that major galaxy–galaxy interactions ($\mu \ge \frac{1}{4}$, where μ is the stellar mass ratio) play a substantial role in triggering the rapid growth phase of BHs in the low-redshift Universe, whilst potentially having a lower influence at high redshift. Approximately 40 per cent of BHs that initiate the rapid BH growth phase at $z$ ≈ 0 do so within ±0.5 dynamical times of a major galaxy–galaxy merger, a fourfold increase above what is expected from the background merger rate. We find that minor mergers ($\frac{1}{10} \le \mu \lt \frac{1}{4}$ ) have a substantially lower influence in triggering the rapid growth phase at all epochs.