James Webb Space Telescope Feed Post

The Relation Between AGN and Host Galaxy Properties: I. Obscured AGN reside in disturbed hosts at 0 < z < 4

JADES v1 mosaic image cutouts of lightly obscured (NH < 1022cm-2) X-ray-selected AGN at 0 < z < 1 (Lyu et al. 2022) in the following NIRCam bands (left to right): F090W, F115W, F150W, F200W, F277W, F356W, F444W. Abstract: The morphology of a galaxy is a manifestation of the complex interplay of physical processes occurring within and around it, and therefore offers indirect clues to its formation and evolution. We use both visual classification and computer vision to verify the suspected connection between galaxy merging activity - as evidenced by a close/merging galaxy pair, or tidal features surrounding an apparently singular system - and AGN activity. This study makes use of JADES JWST/NIRCam imagery, along with an unprecedentedly complete sample of AGN built using JWST/MIRI photometry in the same field. This 0.9-25 micron dataset enables constraints on the host galaxy morphologies of the broadest possible range of AGN beyond z~1, including heavily obscured examples missing from previous studies. We consider two AGN samples, one consisting of lightly to highly obscured X-ray-selected AGN (Lyu et al. 2022), and the other, presumed Compton-thick mid-infrared-bright/X-ray-faint AGN recently revealed by MIRI (Lyu et al. 2023). Both samples contain a significant fraction of host galaxies with disturbed morphologies at all redshifts sampled, and increasingly so towards higher redshift and AGN bolometric luminosity. The most obscured systems show the highest fraction of strongly disturbed host galaxies at 95±4%, followed by the moderately and unobscured/lightly obscured subsets at 78±6% and 63±6.5%, respectively. From this pattern of disturbances, we conclude that mergers are common amongst obscured AGN, and that the obscured AGN phase may mark a period of significant SMBH growth. This finding presents tension with the leading model on AGN fueling mechanisms (Hopkins et al. 2014) that needs reconciling.