TRINITY VI: connection between galaxy star formation rates and supermassive black hole accretion rates from z = 0 − 10

We infer supermassive black hole (SMBH) accretion rates and Eddington ratios as a function of SMBH/host galaxy mass and redshift with the empirical Trinity model of dark matter halo–galaxy–SMBH connection. The galaxy–SMBH mass and growth rate connection from Trinity match galaxy observables from 0 < z < 13 and SMBH observables from 0 < z < 6.5⁠. Key findings include: (1) the ratio between cosmic SMBH accretion rate and galaxy star formation rate stays constant at ~ 2 x 10⁻³ from z = 0 - 4⁠, and decreases by 2 orders of magnitude from ⁠z = 4 -10; (2) the average SMBH Eddington ratio η increases towards higher redshifts, nearly reaching η = 1 at ⁠z ~ 10; (3) at fixed redshift for z < 3⁠, SMBHs/galaxies with higher masses have lower ⁠η, consistent with active galactic nucleus (AGN) downsizing; (4) the average ratio of specific SMBH accretion rate (SBHAR⁠⁠) to average specific star formation rate (SSFR⁠⁠) is nearly mass-independent, with a value SBHAR/SSFR ~ 1⁠, which decreases slightly from z = 10 to z = 0⁠; (5) similar to galaxies, SMBHs reach their peak efficiency to convert baryons into mass when host haloes reach 10¹² M⊙; (6) given galaxy and SMBH growth histories from Trinity, the local descendants of 1 < z < 11 overmassive JWST AGNs will remain outliers from the local SMBH mass–galaxy mass relation. These findings combine to give a simple explanation for massive (10⁹ - 10¹⁰⁠⁠) quasars at ⁠z > 6: at these redshifts, dark matter haloes grow with an e-folding time of ~ 45 Myr, driving similar growth in both galaxies and SMBHs.