Galaxy discs regulate the growth of supermassive black holes

Roberts, RJ ORCID: 0009-0005-5917-8043, Davies, JJ and Crain, RA ORCID: 0000-0001-6258-0344 (2026) Galaxy discs regulate the growth of supermassive black holes. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711 (Accepted)

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Abstract

We examine the relationship between the mass of present-day central supermassive black holes (SMBHs, MBH), and the stellar mass (M⋆) and halo mass (M200) of their host galaxies in the EAGLE simulation, and find that scatter about these relations correlates with both halo structure and galaxy morphology. EAGLE reproduces the observed MBH − M⋆ relation, including (qualitatively) its dependence on morphology: at fixed M⋆, disc-dominated galaxies host less massive SMBHs than ellipticals. We show that MBH correlates with M200, as expected if SMBHs are regulated by processes acting on the scale of the host dark matter halo, but exhibits a tighter correlation with the halo binding energy (Ebind), signalling that this quantity, which encodes information about both halo mass and halo structure, is more fundamental to MBH. As with MBH − M⋆, scatter about the MBH − Ebind relation is strongly correlated with morphology. Gas in the central few parsecs of galaxies with present-day discs retains strong rotational support as the galaxy grows, inhibiting inward transport and precluding periods of rapid SMBH growth by gas accretion. In galaxies destined to be present-day ellipticals, however, this rotational support is disrupted, enabling gas to be funnelled onto the central SMBH, triggering rapid growth. Evolution of the mass fraction of stars formed ex-situ indicates that this disruption is caused by galaxy-galaxy interactions and mergers. Our findings corroborate the conclusion of recent studies, based on controlled simulations of an ∼L⋆ galaxy, that prolonged secular galaxy evolution inhibits central SMBH growth.

Item Type:	Article
Additional Information:	This article has been accepted for publication in Monthly Notices of the Astronomical Society, published by Oxford University Press.
Uncontrolled Keywords:	0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Date of acceptance:	30 March 2026
Date of first compliant Open Access:	9 April 2026
Date Deposited:	09 Apr 2026 15:05
Last Modified:	09 Apr 2026 15:05
DOI or ID number:	10.1093/mnras/stag629
URI:	https://researchonline.ljmu.ac.uk/id/eprint/28357

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