CEERS Key Paper III: The Resolved Host Properties of AGN at 3 < z < 5 with JWST

TL;DR

This study uses JWST imaging to analyze the properties of five high-redshift AGN host galaxies, revealing their massive, often spheroidal, and quiescent nature, and suggesting AGN feedback may help maintain galaxy quiescence.

Contribution

First detailed JWST-based morphological and stellar property analysis of AGN hosts at 3<z<5, highlighting their massive, often passive, and spheroidal characteristics.

Findings

Most hosts are massive and spheroidal

Hosts show signs of quenched or post-starburst populations

AGN may help sustain galaxy quiescence

Abstract

We report on the host properties of five X-ray luminous Active Galactic Nuclei (AGN) identified at $3 < z < 5$ in the first epoch of imaging from the Cosmic Evolution Early Release Science Survey (CEERS). Each galaxy has been imaged with the \textit{James Webb Space Telescope} (\jwst) Near-Infrared Camera (NIRCam), which provides spatially resolved, rest-frame optical morphologies at these redshifts. We also derive stellar masses and star formation rates for each host galaxy by fitting its spectral energy distribution using a combination of galaxy and AGN templates. The AGN hosts have an average stellar mass of ${\rm log}(M_{*}/{\rm M_{\odot}} )= 11.0$, making them among the most massive galaxies detected at this redshift range in the current CEERS pointings, even after accounting for nuclear light from the AGN. We find that three of the AGN hosts have spheroidal morphologies, one is a bulge-dominated disk and one host is dominated by point-like emission. None are found to show strong morphological disturbances that might indicate a recent interaction or merger event. Notably, all four of the resolved hosts have rest-frame optical colors consistent with a quenched or post-starburst stellar population. The presence of AGN in passively evolving galaxies at $z>3$ is significant because a rapid feedback mechanism is required in most semi-analytic models and cosmological simulations to explain the growing population of massive quiescent galaxies observed at these redshifts. Our findings are in general agreement with this picture and show that AGN can continue to inject energy into these systems after their star formation is curtailed, possibly helping to maintain their quiescent state.