Tracing the AGN-Merger Connection: insights from cosmological simulations and JWST mock observations
University of Seoul（首尔大学）；Flatiron Institute（平顿研究所）；Colby College（科尔比学院）；École Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院）；University of Copenhagen（哥本哈根大学）；Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；University of Florida（佛罗里达大学）；Space Telescope Science Institute（太空望远镜科学研究所）；Korea Institute for Advanced Study (KIAS)（韩国高等科学研究院）
Hannah Jhee, Ena Choi, Rachel S. Somerville, Dale D. Kocevski, Michaela Hirschmann, Thorsten Naab, Desika Narayanan, Intae Jung, Juhan Kim
备注：
16 pages, 12 figures, Accepted for publication in MNRAS
星系合并长期以来被认为是一种将气体引导到银河中心的机制，可能触发超大质量黑洞（SMBH）的吸积并点燃活跃星系核（AGN）。尽管模拟通常支持这一情景，但观测研究在AGN-合并关系方面产生了矛盾的结果。在本研究中，我们分析了跨越红移0.5 < z < 3的31个宇宙学放大模拟中的星系。我们利用六维暗物质粒子信息构建详细的合并树来识别合并，并通过SMBH吸积历史来识别AGN活动。为了弥合模拟与观测之间的差距，我们生成了类似JWST的模拟图像，并提取了非参数化的形态学参数。在五维空间（四个形态学参数和红移）中使用k-最近邻（KNN）分类器，我们识别了模拟观测数据集中的合并。我们的分析揭示了在合并系统中AGN活动的统计学显著增强，特别是在较低的红移（0.5 < z < 0.9）中，其中中心气体储备更为耗尽。这支持了在内部气体储备较低的环境中，合并对AGN触发的贡献更为显著，而在气体丰富的系统中其影响可能不那么明显。然而，当仅依赖于模拟观测的形态学分类时，观察到的AGN-合并关系会减弱，尤其是在更高的红移中。这突显了在观测上检测由合并引发的AGN活动的挑战，并强调了结合模拟与现实的模拟观测以充分理解AGN-合并关系的重要性。
英文摘要：
Galaxy mergers have long been proposed as a mechanism for funneling gas toward galactic centres, potentially triggering accretion onto supermassive black holes (SMBHs) and igniting active galactic nuclei (AGN). While simulations often support this scenario, observational studies have yielded conflicting results regarding the AGN-merger connection. In this study, we analyze 31 galaxies from cosmological zoom-in simulations spanning redshifts $0.5 < z < 3$. We identify mergers using detailed merger trees based on six-dimensional dark matter particle information and identify AGN activity through SMBH accretion histories. To bridge the gap between simulations and observations, we generate mock JWST-like images and extract non-parametric morphological parameters. Employing a $k$-nearest neighbours (KNN) classifier in a five-dimensional space (four morphological parameters and redshift), we identify mergers in the mock-observed dataset. Our analysis reveals a statistically significant enhancement of AGN activity in merging systems, particularly at lower redshifts ($0.5 < z < 0.9$), where central gas reservoirs are more depleted. This supports the view that mergers contribute more significantly to AGN triggering in environments with low internal gas reservoirs, while their impact may be less pronounced in gas-rich systems. However, when relying solely on morphological classifications from mock observations, the observed AGN-merger connection weakens, especially at higher redshifts. This underscores the challenges in detecting merger-induced AGN activity observationally and highlights the importance of combining simulations with realistic mock observations to fully understand the AGN-merger relationship.
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Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)（国家天体物理学、光学和电子学研究所）；Centro de Astrobiologia (CAB), CSIC-INTA（天体生物学中心（CSIC-INTA））；Universidad Nacional Autónoma de México, Instituto de Astronomía（墨西哥国立自治大学天文研究所）
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Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Fakultät für Physik und Astronomie, Universität Heidelberg（海德堡大学物理与天文学院）；Space Telescope Science Institute（太空望远镜科学研究所）
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University of Kansas（堪萨斯大学）；Rochester Institute of Technology（罗切斯特理工学院）；Colby College（科尔比学院）；Space Telescope Science Institute（太空望远镜科学研究所）；NASA-Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Texas A&M University（得克萨斯农工大学）
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Università di Firenze（佛罗伦萨大学）；INAF – Arcetri Astrophysical Observatory（意大利国家天体物理研究所阿切特里天文台）；European Southern Observatory（欧洲南方天文台）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）
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Università di Bologna（博洛尼亚大学）；INAF Astrophysics and Space Science Observatory Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）；University of Copenhagen（哥本哈根大学）；Swinburne University of Technology（斯威本科技大学）；University of Toronto（多伦多大学）
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University of California, Santa Barbara（加州大学圣塔芭芭拉分校）；Center for Astrophysics | Harvard & Smithsonian（哈佛-史密森天体物理中心）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）
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Waseda University（早稻田大学）；University of Tsukuba（筑波大学）
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Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Observatoire de Paris, LERMA, PSL University（巴黎天文台，PSL大学）；Université Paris-Cité（巴黎西岱大学）；Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心（CSIC-INTA））；University of Arizona（亚利桑那大学）；Space Telescope Science Institute（太空望远镜科学研究所）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）
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University of Alberta（阿尔伯塔大学）；University of Oxford（牛津大学）；Harvard & Smithsonian（哈佛-史密森天体物理中心）；Raytheon（雷神公司）；Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；Universiteit Gent（根特大学）；University of Washington（华盛顿大学）；Flatiron Institute（平顿研究所）；University of Florida（佛罗里达大学）；Northwestern University（西北大学）；The Ohio State University（俄亥俄州立大学）
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The University of Nottingham（诺丁汉大学）；University of Edinburgh（爱丁堡大学）；Kavli Institute for Cosmology（卡弗里宇宙学研究所）；Tata Institute of Fundamental Research（塔塔基础研究所）；Leibniz-Institut für Astrophysik Potsdam（波茨坦阿斯特拉物理研究所）
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