The rapid growth phase of supermassive black holes

McAlpine, Stuart; Bower, Richard G.; Rosario, David J.; Crain, Robert A.; Schaye, Joop; Theuns, Tom

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 (M200  ≈1012.4 M⊙ at z ≈ 0 decreasing to M200  ≈1011.2 M⊙ at z ≈ 6). Instead, BHs enter the rapid growth phase at a fixed critical halo virial temperature (Tvir ≈ 105.6 K). We additionally show that major galaxy–galaxy interactions ( μ≥14 , 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 ( 110≤μ<14 ) have a substantially lower influence in triggering the rapid growth phase at all epochs.

Citation

McAlpine, S., Bower, R. G., Rosario, D. J., Crain, R. A., Schaye, J., & Theuns, T. (2018). The rapid growth phase of supermassive black holes. Monthly Notices of the Royal Astronomical Society, 481(3), 3118-3128. https://doi.org/10.1093/mnras/sty2489

• Journal Article Type: Article
• Acceptance Date: Sep 7, 2018
• Online Publication Date: Sep 11, 2018
• Publication Date: Dec 11, 2018
• Deposit Date: Oct 18, 2018
• Publicly Available Date: Oct 18, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 481
• Issue: 3
• Pages: 3118-3128
• DOI: https://doi.org/10.1093/mnras/sty2489
• Public URL: https://durham-repository.worktribe.com/output/1316083