Active Galactic Nuclei and Host Galaxies in COSMOS-Web. II. First Look At the Kiloparsec-scale Dual and Offset AGN Population

作者：Junyao Li, Ming-Yang Zhuang, Yue Shen, Marta Volonteri, Nianyi Chen, Tiziana DiMatteo · 发表于：The Astrophysical Journal · 年份：2025 · DOI：10.3847/1538-4357/adbae2 · 被引用次数：9 · 研究领域：Galaxies: Formation, Evolution, Phenomena、Astronomy and Astrophysical Research、Gamma-ray bursts and supernovae

Abstract Kiloparsec-scale dual and offset active galactic nuclei (AGNs) are signposts of accreting supermassive black holes (SMBHs) triggered during late-stage galaxy mergers, offering crucial insights into the coevolution of SMBHs and galaxies. However, robustly confirmed systems at high redshift (e.g., z > 1) are scarce and biased toward the most luminous and unobscured systems. In this study, we systematically search for kiloparsec-scale (projected separation <15 kpc) dual and offset AGNs around 571 moderate-luminosity, X-ray-selected AGNs, including the obscured population, utilizing deep Hubble Space Telescope Advanced Camera for Surveys/F814W and multiband JWST NIRCam imaging from the COSMOS-Web survey. We identify 59 dual and 30 offset AGN candidates in late-stage major mergers based on spatially resolved spectral energy distribution analyses. This translates to ∼28 and ∼10 bona fide dual and offset AGNs, using a probabilistic pair-counting scheme to minimize chance superpositions. Notably, the fraction of dual and offset AGNs among moderate-luminosity ( L bol ∼ 10 43 −10 46 erg s −1 ) obscured AGNs is nearly 2 orders of magnitude higher than that of the most luminous, unobscured quasar pairs. We find tentative evidence for an increasing pair fraction among AGNs with redshift (from a few percent at z ∼ 0.5 to ∼ 22 . 9 − 17.7 + 27.5 % at z ∼ 4.5) and a higher occurrence rate of dual over offset AGNs. There is no pileup of dual...