The Most Obscured AGNs in the XMM-SERVS Fields
Wei Yan, W. N. Brandt, Fan Zou, Shifu Zhu, Chien‐Ting Chen, Ryan C. Hickox, Bin Luo, Qingling Ni, D. M. Alexander, F. E. Bauer, C. Vignali, Fabio Vito
Abstract
Abstract We perform X-ray spectral analyses to derive the characteristics (e.g., column density, X-ray luminosity) of ≈10,200 active galactic nuclei (AGNs) in the XMM-Spitzer Extragalactic Representative Volume Survey, which was designed to investigate the growth of supermassive black holes across a wide dynamic range of cosmic environments. Using physical torus models (e.g., Borus02) and a Bayesian approach, we uncover 22 representative Compton-thick (CT; N H > 1.5 × 10 24 cm −2 ) AGN candidates with good signal-to-noise ratios as well as a large sample of 136 heavily obscured AGNs. We also find an increasing CT fraction ( f CT ) from low ( z < 0.75) to high ( z > 0.75) redshift. Our CT candidates tend to show hard X-ray spectral shapes and dust extinction in their spectral energy distribution fits, which may shed light on the connection between AGN obscuration and host-galaxy evolution.