Co-evolution of AGN and Host Galaxies across Cosmic Time Using JWST data

Abstract

Understanding the complex co-evolution of active galactic nuclei (AGN) and their host galaxies across cosmic time remains a fundamental challenge, particularly in identifying how the physical drivers of galaxy diversity evolve from the early Universe to the present day. To understand this, we use a multi-wavelength JWST catalog of 2,709 sources cross-matched from the SMILES and JWST Advanced Deep Extragalactic Survey (JADES) surveys, spanning lookback times from 0.8 to 12.9 Gyr ($0.05 <z <6$). Using Pearson correlation matrix, we find AGN luminosity ($L_{\mathrm{AGN}}$) strongly correlates ($\sim0.8$) with star formation rate (SFR) and dust luminosity ($L_{\mathrm{dust}}$), weakly correlates ($\sim0.5$) with stellar mass ($M_\star$) and anti-correlates ($\sim -0.4$) with star formation history (SFH) duration and stellar age (Age$_\star$). However, the apparent anti-correlation observed between galaxy age and AGN luminosity is driven by cosmic time rather than by a direct physical connection. Using Principal Component Analysis (PCA), we find that galaxy diversity is fundamentally governed by two principal components: AGN and galaxy activity, and stellar age. At higher redshifts, AGN accretion, star formation, and dust emission are tightly synchronized, reflecting gas-rich conditions in the early Universe. In contrast, the present Universe exhibits a clear bimodal structure in host-dominated systems ($f_{\mathrm{AGN}} \leq 0.2$), separating quiescent and star-forming galaxies. Our results demonstrate that AGN luminosity is primarily governed by the host galaxy's current cold-gas supply, of which recent star formation is a close observational tracer, with galaxy mass setting the overall potential. This highlights a co-evolution scenario in which black hole growth and star formation are tightly linked, particularly at early cosmic epochs.