Black Hole and Galaxy Coevolution in Moderately Luminous Active Galactic Nuclei at z ∼ 1.4 in SXDF

Abstract

Abstract We investigate the relation of black hole mass versus host stellar mass and that of mass accretion rate versus star formation rate (SFR) in moderately luminous ( ), X-ray selected broad-line active galactic nuclei (AGNs) at z = 1.18–1.68 in the Subaru/XMM-Newton Deep Field. The far-infrared to far-ultraviolet spectral energy distributions of 85 AGNs are reproduced with the latest version of Code Investigating GALaxy Emission (CIGALE), where the AGN clumpy torus model SKIRTOR is implemented. Most of their hosts are confirmed to be main-sequence star-forming galaxies. We find that the mean ratio of the black hole mass (M BH) to the total stellar mass (M stellar) is , which is similar to the local black hole–to–bulge mass ratio. This suggests that if the host galaxies of these moderately luminous AGNs at z ∼ 1.4 are dominated by bulges, they already established the local black hole mass–bulge mass relation; if they are disk dominant, their black holes are overmassive relative to the bulges. The AGN bolometric luminosities and SFR show a good correlation with ratios higher than that expected from the local black hole-to-bulge mass relation, suggesting that these AGNs are in a SMBH-growth dominant phase.