Revealing the relation between black hole growth and host-galaxy compactness among star-forming galaxies
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Date
2021
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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 approximate to 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 (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, Sigma(1), is utilized to represent host-galaxy compactness in our study. We find that the BHAR-Sigma(1) relation is stronger than either the BHAR-M-* or BHAR-SFR relation among SF galaxies, and this BHAR-Sigma(1) relation applies to both bulge-dominated galaxies and galaxies that are not dominated by bulges. This BHAR-Sigma(1) 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 similar to kpc of the galaxy. This BHAR-Sigma(1) 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.
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galaxies: active, galaxies: evolution, galaxies: nuclei, X-rays: galaxies