在即将到来的天基干涉仪LISA的潜在毫赫兹引力波（GW）源中，有极端或中等质量比的螺旋（EMRI/IMRI）。这些事件涉及质量范围为$10^5 M_{\odot} \lesssim M \lesssim 10^7 M_{\odot}$的超大质量黑洞与质量小得多的黑洞的合并。一个子集的E/IMRIs预计将发生在吸积盘的活动星系核（AGN），在那里施加的扭矩盘可以干扰的inspiral，并导致相移的GW波形。在这里，我们使用一套二维流体动力学模拟与移动网格代码DISCO提出了一个系统的研究光盘扭矩。我们测量吸气BH上的扭矩，并计算相应的波形偏差作为二元质量比$q\equiv M_2/M_1$、圆盘粘度（$α$）和气体温度（或等效马赫数; $\mathcal{M}$）的函数。我们发现，气体扭矩的绝对值是在先前确定的行星迁移扭矩的数量级，但其精确的值和符号依赖于这些参数的组合，非平凡的。对于嵌入活动星系核盘中的双星，其表面密度高于$Σ_0\ge10^{4-6} \rm \, g cm^{-2}$（取决于$q$、$α$和$\mathcal{M}$）的气体印记可以用激光束散射（LISA）检测到。在具有较高粘度的圆盘中，以及在LISA最敏感的频率处检测到的E/IMRI中，偏差最明显。在较冷的磁盘扭矩表现出显着的依赖于GW驱动的inspiral率，以及在后期阶段的inspiral的强烈波动。我们的研究结果进一步表明，LISA可能能够对活动星系核盘参数和盘-卫星相互作用的物理特性进行约束。
英文摘要：
Among the potential milliHz gravitational wave (GW) sources for the upcoming space-based interferometer LISA are extreme- or intermediate-mass ratio inspirals (EMRI/IMRIs). These events involve the coalescence of supermassive black holes in the mass range $10^5 M_{\odot} \lesssim M \lesssim 10^7 M_{\odot}$ with companion BHs of much lower masses. A subset of E/IMRIs are expected to occur in the accretion discs of active galactic nuclei (AGN), where torques exerted by the disc can interfere with the inspiral and cause a phase shift in the GW waveform. Here we use a suite of two-dimensional hydrodynamical simulations with the moving-mesh code DISCO to present a systematic study of disc torques. We measure torques on an inspiraling BH and compute the corresponding waveform deviations as a function of the binary mass ratio $q\equiv M_2/M_1$, the disc viscosity ($α$), and gas temperature (or equivalently Mach number; $\mathcal{M}$). We find that the absolute value of the gas torques is within an order of magnitude of previously determined planetary migration torques, but their precise value and sign depends non-trivially on the combination of these parameters. The gas imprint is detectable by LISA for binaries embedded in AGN discs with surface densities above $Σ_0\ge10^{4-6} \rm \, g cm^{-2}$, depending on $q$, $α$ and $\mathcal{M}$. Deviations are most pronounced in discs with higher viscosities, and for E/IMRIs detected at frequencies where LISA is most sensitive. Torques in colder discs exhibit a noticeable dependence on the GW-driven inspiral rate as well as strong fluctuations at late stages of the inspiral. Our results further suggest that LISA may be able to place constraints on AGN disc parameters and the physics of disc-satellite interaction.
From S2 to LISA: Astrometric Bounds on Extreme-Mass-Ratio Inspirals and Bursts
CERN（欧洲核子研究中心）；Dipartimento di Fisica, “Sapienza” Università di Roma & Sezione INFN Roma1（罗马第一大学物理系与INFN罗马第一分部）；Weizmann Institute of Science（魏茨曼科学研究所）
Chaotic migration of LISA Extreme Mass Ratio Inspirals in a turbulent accretion disk: effect on waveform de-phasing
Center for Cosmology and Particle Physics, Physics Department, New York University（纽约大学物理系宇宙学与粒子物理中心）；Department of Astrophysics, University of Zurich（苏黎世大学天体物理学系）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；National Astronomical Observatory of Japan（日本国立天文台）；Department of Astronomy & Astrophysics, University of California, Santa Cruz（加州大学圣克鲁兹分校天文与天体物理学系）；Institute for Advanced Studies, Tsinghua University（清华大学高等研究院）
What Fraction of Extreme Mass Ratio Inspirals That Merge After the LISA Mission Ends Are Detectable?
Oregon State University（俄勒冈州立大学）；Universities Space Research Association（大学空间研究协会）；NASA Marshall Space Flight Center（美国国家航空航天局马歇尔太空飞行中心）；California Institute of Technology（加州理工学院）；University of Southampton（南安普顿大学）
Extreme mass ratio inspirals from the Hills mechanism, The eccentricity distribution of Hills EMRIs in LISA
Leiden University（莱顿大学）；Università degli Studi di Trento（特伦托大学）；Università degli Studi di Milano-Bicocca（米兰比可卡大学）；INFN - Sezione di Milano-Bicocca（意大利国家核物理研究所米兰比可卡分部）；Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究院）
Revealing massive black hole astrophysics: The potential of hierarchical inference with extreme mass-ratio inspiral observations
Institute for Gravitational Research, University of Glasgow（格拉斯哥大学引力研究所）；Institute for Gravitational Wave Astronomy & School of Physics and Astronomy, University of Birmingham（伯明翰大学引力波天文学所与物理天文学院）
Multimessenger prospects of quasi-periodic eruptions
Institute of Theoretical Physics, Faculty of Mathematics and Physics（数学物理学院理论物理研究所）；Dipartimento di Fisica “A. Pontremoli”, Università degli Studi di Milano（米兰大学A. Pontremoli物理系）；Dipartimento di Fisica “G. Occhialini”, Università degli Studi di Milano-Bicocca（米兰比可卡大学G. Occhialini物理系）
Extreme Love in the SPA: constraining the tidal deformability of supermassive objects with extreme mass ratio inspirals and semi-analytical, frequency-domain waveforms
Extreme Mass Ratio Inspirals in Light of Quasi-periodic Eruptions: Milli-Hertz Gravitational Wave Background
Tsung-Dao Lee Institute, Shanghai Jiao-Tong University（上海交大李政道研究所）；School of Physics & Astronomy, Shanghai Jiao-Tong University（上海交通大学物理与天文学院）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）；Kavli Institute for Astronomy and Astrophysics at Peking University（北京大学科维理天文与天体物理研究所）
Hubble constant measurement from QPEs as electromagnetic counterparts to extreme mass ratio inspirals
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；School of Physics and Physical Engineering, Qufu Normal University（曲阜师范大学物理工程学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（教育部现代天文学与天体物理学重点实验室（南京大学））
Ab uno disce omnes: Single-harmonic search for extreme mass-ratio inspirals
European Space Agency (ESA), European Space Research and Technology Centre (ESTEC)（欧洲空间局（ESA），欧洲空间研究与技术中心（ESTEC））；Universitá degli Studi di Milano-Bicocca（米兰比可卡大学）；INFN, Sezione di Milano-Bicocca（意大利国家核物理研究所，米兰比可卡分校）；University of Birmingham（伯明翰大学）
