Black Hole Growth Is Mainly Linked to Host-galaxy Stellar Mass Rather Than Star Formation Rate

We investigate the dependence of black hole accretion rate (BHAR) on host-galaxy star formation rate (SFR) and stellar mass (M _∗) in the CANDELS/GOODS-South field in the redshift range of. Our sample consists of galaxies, allowing us to probe galaxies with and/or. We use sample-mean BHAR to approximate long-term average BHAR. Our sample-mean BHARs are derived from the Chandra Deep Field-South 7 Ms observations, while the SFRs and M _∗ have been estimated by the CANDELS team through spectral energy distribution fitting. The average BHAR is correlated positively with both SFR and M _∗, and the BHAR-SFR and BHAR-M _∗ relations can both be described acceptably by linear models with a slope of unity. However, BHAR appears to be correlated more strongly with M _∗ than SFR. This result indicates that M _∗ is the primary host-galaxy property related to supermassive black hole (SMBH) growth, and the apparent BHAR-SFR relation is largely a secondary effect due to the star-forming main sequence. Among our sources, massive galaxies () have significantly higher BHAR/SFR ratios than less massive galaxies, indicating that the former have higher SMBH fueling efficiency and/or higher SMBH occupation fraction than the latter. Our results can naturally explain the observed proportionality between and M _∗ for local giant ellipticals and suggest that their is higher than that of local star-forming galaxies. Among local star-forming galaxies, massive systems might have higher compared to dwarfs.