Poster Presentation

Emergence of AGN in galaxy clusters: the relationship among AGN, environment, and cluster-cluster mergers

Author(s): Yoshiki Toba (NAOJ), Aoi Hashiguchi (Nara Women's U.), Naomi Ota (Nara Women's U.), Masamune Oguri (Chiba U.), Nobuhiro Okabe (Hiroshima U.), Yoshihiro Ueda (Kyoto U.), Masatoshi Imanishi (NAOJ), and CAMIRA-AGN collaboration

Presenter: Yoshiki Toba (NAOJ)

We present the statistical properties of active galactic nuclei (AGNs) in approximately one million member galaxies of galaxy groups and clusters, selected using the Subaru Hyper Suprime-Cam (HSC), so-called CAMIRA clusters. The focus of our investigation is on the AGN power fraction (fAGN), which is the proportion of the contribution of AGNs to the total infrared (IR) luminosity, LIR(AGN)/LIR, and how the fAGN depends on (i) the cluster redshift (zcl) and (ii) the distance from the cluster center (R/R200). We gathered data in the ultraviolet--mid-IR range and performed spectral energy distribution (SED) fitting using the CIGALE code to investigate fAGN of CAMIRA member galaxies. We find that (i) the value of fAGN in CAMIRA clusters increases with zcl, with a steeper slope than that of field galaxies and (ii) fAGN is higher in cluster outskirts, especially in the massive merging clusters. These results suggest that the emergence of the AGN population depends on the redshift and environment and that galaxy groups and clusters at high redshifts play a crucial role in AGN evolution (Toba et al. 2024, ApJ, in press.).