TRINITY IV: Predictions for Supermassive Black Holes at $z \gtrsim 7$

TL;DR

This paper uses the TRINITY model to predict the evolution and properties of supermassive black holes at high redshifts, providing insights into their growth, host haloes, and observational signatures with JWST and future surveys.

Contribution

The study introduces a comprehensive model linking high-redshift SMBHs with their host galaxies and haloes, constrained by extensive datasets, and offers new predictions for SMBH populations and origins at $z sim 7$ and beyond.

Findings

SMBHs > 10^9 M_\odot$ increase six orders of magnitude from $z extasciitilde 10$ to 2.

High-redshift SMBHs reside in haloes of a few times 10^{12} M_\odot$.

JWST AGN observations align with the SMBH-galaxy mass relation from TRINITY.

Abstract

We present predictions for the high-redshift halo-galaxy-supermassive black hole (SMBH) connection from the TRINITY model. Constrained by a comprehensive compilation of galaxy ($0\leq z \leq 10$) and SMBH datasets ($0\leq z \leq 6.5$), TRINITY finds: 1) The number of SMBHs with $M_\bullet > 10^9 M_\odot$ in the observable Universe increases by six orders of magnitude from $z\sim10$ to $z\sim2$, and by another factor of $\sim 3$ from $z\sim2$ to $z=0$; 2) The $M_\bullet > 10^9/10^{10} M_\odot$ SMBHs at $z\sim 6$ live in haloes with $\sim (2-3)/(3-5) \times 10^{12} M_\odot$; 3) the new JWST AGNs at $7\lesssim z \lesssim 11$ are broadly consistent with the median SMBH mass-galaxy mass relation for AGNs from TRINITY; 4) Seeds from runaway mergers in nuclear star clusters are viable progenitors for the SMBHs in GN-z11 ($z=10.6$) and CEERS_1019 ($z=8.7$); 5) $z=6-10$ quasar luminosity functions from wide area surveys by, e.g., Roman and Euclid, will reduce uncertainties in the $z=6-10$ SMBH mass-galaxy mass relation by up to $\sim 0.5$ dex.