2025/10/15 by Bovornpratch Vijarnwannaluk, Vijarnwannaluk, Bovornpratch, Zhen-Kai Gao +41
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2510.13719
We investigate the stellar shape and size-mass relationship of X-ray selected Active Galactic Nuclei (AGN) host galaxies using the high-angular resolution and deep sensitivity in the near-infrared of the COSMOS-Web JWST survey field. We present the rest-frame 1-μm size, stellar mass, Sersic index, axis-ratio, Gini-M20 parameters of 690 moderate luminosity AGNs between redshift 0-3 and with stellar mass log Ms∼ 10.75. We find that AGN host galaxies have an effective radius of 1-5 kpc, which is between star-forming (SFG) and quiescent galaxies (QGs) of the same stellar mass. AGN hosts have similar size-mass trends as SFG and QGs, being smaller at higher redshift for the same stellar mass. The slope of the size-mass relationship of AGN host galaxies is steeper than that of star-forming galaxies. Their rest-frame 1μm stellar morphology indicates a significant spheroidal component. We observed a low merger fraction (6%) in our sample as well as substructures similar to disks, bars, and spiral arms in the residual images, which are in tension with evolutionary pathways that require major mergers. However, it may also be due to the different timescales between mergers and AGN activity.