Observational searches for dual active galactic nuclei (dAGNs) at kiloparsec separations are crucial for understanding the role of galaxy mergers in the evolution of galaxies. In addition, kpc-scale dAGNs may serve as the parent population of merging massive black hole (MBH) binaries, an important source of gravitational waves. We use a semi-analytical model to describe the orbital evolution of unequal mass MBH pairs under the influence of stellar and gaseous dynamical friction in post-merger galaxies. We quantify how the detectability of approximately 40,000 kpc-scale dAGNs depends on the structure of their host galaxies and the orbital properties of the MBH pair. Our models indicate that kpc-scale dAGNs are most likely to be detected in gas-rich post-merger galaxies with smaller stellar bulges and relatively massive, rapidly rotating gas disks. The detectability is also increased in systems with MBHs of comparable masses following low eccentricity prograde orbits. In contrast, dAGNs with retrograde, low eccentricity orbits are some of the least detectable systems among our models. The dAGNs in models in which the accreting MBHs are allowed to exhibit radiative feedback are characterized by a significantly lower overall detectability. The suppression in detectability is most pronounced in gas-rich merger remnant galaxies, where radiation feedback is more likely to arise. If so, then large, relatively gas poor galaxies may be the best candidates for detecting dAGNs.
Chandra X-ray and Hubble Space Telescope Imaging of Optically Selected Kiloparsec-Scale Binary Active Galactic Nuclei II: Host Galaxy Morphology and AGN Activity
Hubble Space Telescope Wide Field Camera 3 Identifies an $r_p$ = 1 Kpc Dual Active Galactic Nucleus in the Minor Galaxy Merger SDSS J0924+0510 at z = 0.1495
Pairing of Massive Black Holes in Merger Galaxies Driven by Dynamical Friction
出于对大质量黑洞（MBH）对在千秒差距的观测搜索，我们开发了一个半解析模型来描述它们的轨道演化的影响下，恒星和气体动力学摩擦（DF）。这项研究的目的是确定合并残余星系和MBH的性质如何影响形成距离< 1 pc的紧密MBH对的可能性和时间尺度。我们计算了大约40,000种配置，涵盖了广泛的宿主星系的属性，并研究了它们对不等质量MBH对轨道演化的影响。我们发现，在气体质量分数为10^6太阳质量和质量比> 1/4的残余星系中，在哈勃时间内MBH配对的百分比大于80%< 20% and in galaxies hosting MBH pairs with total mass >。在这些星系中，以最快形成紧密的引力束缚MBH为特征的残余星系具有以下一个或多个性质：（1）大的恒星隆起，（2）质量相当的MBH和（3）星系气体盘以接近圆周速度旋转。在这样的星系中，具有最短螺旋时间的MBH，可能是合并MBH的祖先，要么在圆形的逆行轨道上，要么在非常偏心的逆行轨道上。我们的模型还表明，具有相反性质的残余星系，主机缓慢演变的MBH对，是最有可能的主机双活动星系核在千秒差距。
Rapid growth in a dual AGN during a gas-rich merger at z~4.5
International Gemini Observatory/NSF NOIRLab（国际双子星天文台/美国国家光学红外天文研究实验室）；INAF - Osservatorio di Astrofisica e Scienza dello Spazio di 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）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（加泰罗尼亚高级研究理事会））；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究学院）；Department of Astronomy and Yonsei University Observatory, Yonsei University（延世大学天文学系及延世大学天文台）；Dipartimento di Fisica e Astronomia “Augusto Righi”, Università di Bologna（博洛尼塔大学“奥古斯托·里吉”物理与天文学系）；Department of Physics and Astronomy, Clemson University（克莱姆森大学物理与天文学系）；Institut d’Astrophysique de Paris (UMR 7095: CNRS & Sorbonne Universite)（巴黎天体物理研究所）；TU Dresden, Institute of Nuclear and Particle Physics（德累斯顿工业大学核与粒子物理研究所）；DESY（德国电子同步辐射实验室）；Deutsches Zentrum für Astrophysik（德国天体物理学中心）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；NSF NOIRLab, Gemini Observatory（美国国家光学红外天文研究实验室双子星天文台）；Department of Physics, University of Seoul（首尔大学物理系）；Department of Physics, University of Maryland Baltimore County（马里兰大学巴尔的摩分校物理系）
