Revealing the relation between black hole growth and host-galaxy compactness among star-forming galaxies. Issue 4 (13th November 2020)

• Record Type: Journal Article
• Authors: Ni, Q; Brandt, W N; Yang, G; Leja, J; Chen, C-T J; Luo, B; Matharu, J; Sun, M; Vito, F; Xue, Y Q; Zhang, K
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 500:Issue 4(2021)
• Page Start: 4989
• Page End: 5008
• Publication Date: 2020-11-13
• Subjects: galaxies: active -- galaxies: evolution -- galaxies: nuclei -- X-rays: galaxies; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa3514
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Recent studies show that a universal relation between black hole (BH) growth and stellar mass ( M ⋆ ) or star formation rate (SFR) is an oversimplification of BH–galaxy coevolution, and that morphological and structural properties of host galaxies must also be considered. Particularly, a possible connection between BH growth and host-galaxy compactness was identified among star-forming (SF) galaxies. Utilizing ≈6300 massive galaxies with I 814W < 24 at z < 1.2 in the Cosmic Evolution Survey (COSMOS) field, we perform systematic partial correlation analyses to investigate how sample-averaged BH accretion rate ($\rm \overline{BHAR}$ ) depends on host-galaxy compactness among SF galaxies, when controlling for morphology and M ⋆ (or SFR). The projected central surface mass density within 1 kpc, Σ1, is utilized to represent host-galaxy compactness in our study. We find that the $\rm \overline{BHAR}$ –Σ1 relation is stronger than either the $\rm \overline{BHAR}$ – M ⋆ or $\rm \overline{BHAR}$ –SFR relation among SF galaxies, and this $\rm \overline{BHAR}$ –Σ1 relation applies to both bulge-dominated galaxies and galaxies that are not dominated by bulges. This $\rm \overline{BHAR}$ –Σ1 relation among SF galaxies suggests a link between BH growth and the central gas density of host galaxies on the kpc scale, which may further imply a common origin of the gas in the vicinity of the BH and in the central ∼kpc of the galaxy. This $\rm \overline{BHAR}$ –Σ1 relation can also be interpreted as the relation between BH growth and the central velocity dispersion of host galaxies at a given gas content (i.e. gas mass fraction), indicating the role of the host-galaxy potential well in regulating accretion on to the BH.