Constraining the AGN tori at cosmic noon using high-resolution JWST imaging and simultaneous SED fitting

Abstract

There is evidence for significant evolution in the gaseous and dust properties of galaxies since the era of cosmic noon ($1\lesssim z\lesssim 2.5$). The well known co-evolution of supermassive black holes with their host galaxies suggests a constant connection between the small-scale (nuclear) and large-scale regions of galaxies. A fundamental component of Active Galactic Nuclei (AGN) is the "torus", a dense, dusty structure that acts as the interface between the accretion disc and the ISM of the host galaxy. The transitional nature of the torus makes it a prime subject to search for evolution since cosmic noon. We use high-resolution near- and mid-IR imaging from the JWST CEERS program to disentangle the emission from the torus in unprecedented detail for 88 X-ray selected AGN at $z\sim2$. We employ a novel SED fitting technique that combines archival low-resolution multi-band photometry at UV to FIR wavelengths with the new high-resolution JWST photometry to constrain essential AGN and torus parameters, such as accretion disc luminosity, torus opening angle, and inclination angle. We demonstrate that this SED fitting approach leads to better AGN characterisation and tighter constraints on AGN parameters. The population-level analysis finds that the Covering Fraction ($CF$) distribution peaks at $\approx0.25$ with a long tail towards higher $CF$. Despite the well-known evolution of the ISM and structural properties of AGN hosts to these redshifts, the $CF$ distribution of our sample does not show any strong statistical difference with that found in local AGN of equivalent luminosity, or with those at intermediate redshifts.