A suggested model for quasi--periodic eruptions (QPEs) from galaxy nuclei invokes a white dwarf in an eccentric orbit about the central massive black hole. I point out that the extreme mass ratio allows the presence of strong Lindblad resonances in the accretion disc. These are important for the stability of mass transfer, and may trigger the eruptions themselves by rapidly transferring angular momentum from the accretion disc (which is likely to be eccentric itself) to the orbiting WD companion at pericentre. I consider the effects of von Zeipel--Lidov--Kozai (ZLK) cycles caused by a perturber on a more distant orbit about the central black hole. I show that ZLK cycles can change the orbital periods of QPE systems on timescales much shorter than the mass transfer time, as seen in ASASSN-14ko, and produce correlated short--term variations of their mass transfer rates and orbital periods, as recently observed in GSN~069. Further monitoring of these sources should constrain the parameters of any perturbing companions. This in turn may constrain the nature of the events creating QPE systems, and perhaps give major insights into how the central black holes in low--mass galaxies are able to grow.
Discovery of Quasi-periodic Eruptions in the Tidal Disruption Event and Extreme Coronal Line Emitter AT2022upj: implications for the QPE/TDE fraction and a connection to ECLEs
A Unified Timescale Relation for Quasi-Periodic Eruptions and Repeated Nuclear Transients
University of Science and Technology of China（中国科学技术大学）；Guizhou University（贵州大学）；Institute of Deep Space Sciences, Deep Space Exploration Laboratory（深空科学研究所，深空探测实验室）
Evolution of Quasi-Periodic Eruptions in the post-TDE Accretion Disk Perturbed by an Orbiting Star
Masaryk University（马萨里克大学）；Institute of Physics of the Czech Academy of Sciences（捷克科学院物理研究所）；Astronomical Institute of the Czech Academy of Sciences（捷克科学院天文研究所）
A Torus Remnant Revealed by the Infrared Echo of Tidal Disruption Event AT 2019qiz: Implications for the Missing Energy and Quasiperiodic Eruption Formation
Quasi-periodic Eruptions from Stellar-mass Black Holes Impacting Accretion Disks in Galactic Nuclei
School of Physics and Astronomy, Sun Yat-sen University（中山大学物理与天文学院）；CSST Science Center for the Guangdong-HongKong-Macau Great Bay Area, Sun Yat-sen University（中山大学粤港澳大湾区深空探测科学中心）；Tsung-Dao Lee Institute, Shanghai Jiao-Tong University（上海交通大学汤川研究所）；School of Physics & Astronomy, Shanghai Jiao-Tong University（上海交通大学物理与天文学院）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）
Radio properties of the quasi-periodic eruption source RXJ1301.9+2747 at parsec scales
Canadian Institute for Theoretical Astrophysics, University of Toronto（多伦多大学理论天体物理研究所）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理学与空间研究研究所）；International Centre for Radio Astronomy Research – Curtin University（科廷大学国际射电天文研究中心）；Department of Astrophysics, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University（拉德堡德大学数学、天体物理学和粒子物理研究所天体物理系）；Centro de Astrobiología (CAB), CSIC-INTA（西班牙国家航空航天技术研究所-西班牙国家科学研究委员会天体生物学中心）
No evidence for a supermassive black hole binary in GSN 069
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）；Institute for Astronomy, School of Physics, Zhejiang University（浙江大学物理学院天体物理研究所）；Center for Cosmology and Computational Astrophysics, Institute for Advanced Study in Physics, Zhejiang University（浙江大学物理学高等研究院宇宙学与计算天体物理中心）；Department of Astronomy, University of Science and Technology of China（中国科学技术大学天文系）
Resolving Oblique Star-Disk Collisions in Quasi-Periodic Eruptions: Numerical Requirements and the Importance of Geometry
University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Nevada Center for Astrophysics, University of Nevada, Las Vegas（内华达大学拉斯维加斯分校内华达天体物理中心）；California Institute of Technology（加州理工学院）
Gravitational Wave Signatures of Quasi-Periodic Eruptions: LISA Detection Prospects for RX J1301.9+2747
The University of Hong Kong（香港大学）；Beijing Institute of Mathematical Sciences and Applications（北京数学科学研究所）；Tata Institute of Fundamental Research（塔塔基础研究所）
Milky Way scattering properties and intrinsic sizes of active galactic nuclei cores probed by very long baseline interferometry surveys of compact extragalactic radio sources
为了研究活动星系核喷流中的同步辐射不透明度和星际介质中的角展宽强度，我们测量了活动星系核（AGN）射电核的角尺寸，分析了它们的天空分布和频率依赖性。我们已经使用档案甚长基线干涉测量（VLBI）数据的3000多个紧凑的河外射电源观察到的频率，$ν$，从2到43 GHz测量观测到的角尺寸的VLBI核心。我们发现在2，5和8 GHz时，通过银道面（$|b|\lesssim10^\circ$）观察到的河外源的角尺寸显著增加，其中约1/3的角尺寸表现出明显的散射。这些辐射源主要在银河棒、天鹅座区域和一个有银河系外圆$220^\circ\lesssim l\lesssim260^\circ$（菲茨杰拉德窗）的区域被探测到。活动星系核的星际散射强度与银河系H $α$强度、自由电子密度和银河系自转测度有关。散射强度对源红移的依赖性是微不足道的，这表明主要的散射屏幕位于我们的银河系。发现Sgr A $^\ast$的角尺寸是天空中观测到的数千个活动星系核中最大的，我们讨论了这一奇怪结果的可能原因。排除河外射电源具有显着的散射，我们发现，不透明的核心在AGN尺度的角尺寸通常为$ν^{-1}$确认预测的锥形同步加速器喷流模型均分。
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）
No evidence for gamma-ray halos around active galactic nuclei resulting from intergalactic magnetic fields
我们分析了Ap. J. Lett.中报道的堆积活动星系核周围的伽马射线晕，2010，722，L39。首先，我们表明，周围的堆叠活动星系核的γ射线的角分布是一致的蟹状星云脉冲星，这是费米/LAT的点源周围的γ射线的角分布。这使得它不太可能晕是由电磁级联TeV光子在星系际空间。然后，我们比较周围的堆叠活动星系核的γ射线的角分布与费米/LAT的点扩散函数（PSF），并确认存在一个多余的PSF以上。然而，我们证明，这种效果的幅度和角度大小是不同的费米/LAT仪器的前部和后部转换的光子，因此是一种仪器效应。
