It has long been recognised that the main obstacle to accretion of gas onto supermassive black holes (SMBHs) is large specific angular momentum. It is feared that the gas settles in a large scale disc, and that accretion would then proceed too inefficiently to explain the masses of the observed SMBHs. Here we point out that, while the mean angular momentum in the bulge is very likely to be large, the deviations from the mean can also be significant. Indeed, cosmological simulations show that velocity and angular momentum fields of gas flows onto galaxies are very complex. Furthermore, inside bulges the gas velocity distribution can be further randomised by the velocity kicks due to feedback from star formation. We perform hydrodynamical simulations of gaseous rotating shells infalling onto an SMBH, attempting to quantify the importance of velocity dispersion in the gas at relatively large distances from the black hole. We implement this dispersion by means of a supersonic turbulent velocity spectrum. We find that, while in the purely rotating case the circularisation process leads to efficient mixing of gas with different angular momentum, resulting in a low accretion rate, the inclusion of turbulence increases this accretion rate by up to several orders of magnitude. We show that this can be understood based on the notion of "ballistic" accretion, whereby dense filaments, created by convergent turbulent flows, travel through the ambient gas largely unaffected by hydrodynamical drag. We derive a simple analytical formula that captures the numerical results to within a factor of a few. Rescaling our results to astrophysical bulges, we argue that this "ballistic" mode of accretion could provide the SMBHs with a sufficient supply of fuel without the need to channel the gas via large-scale discs or bars, and therefore that star formation in bulges can be a strong catalyst for SMBH accretion.
Spoon-Feeding Giant Stars to Supermassive Black Holes: Episodic Mass Transfer from Evolving Stars and Their Contribution to the Quiescent Activity of Galactic Nuclei
The Environmental Switch in Black Hole Feeding: Bar-Driven vs. Merger-Driven Growth in IllustrisTNG50
Indian Institute of Science, Education and Research (IISER) Tirupati（印度科学教育与研究学院提鲁帕蒂分校）；Department of Space, Platenary and Astronomical Science and Engineering, Indian Institute of Technology (IIT), Kanpur（坎普尔印度理工学院空间、行星与天文学科学与工程系）
BlackHoleWeather -- Spin-coupled chaotic cold accretion across the meso-scale: Morphology and thermodynamics
University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学）；Universidad de Santiago de Chile（智利圣地亚哥大学）；CIRAS, Universidad de Santiago de Chile（智利圣地亚哥大学 CIRAS）；INAF – Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；Science and Technology Institute, Universities Space Research Association（大学太空研究协会科学与理工学院）；INAF – Astronomical Observatory of Rome（意大利国家天体物理研究所罗马天文台）；Department of Physics, University of Rome “Tor Vergata”（罗马托尔维尔加塔大学物理系）
BlackHoleWeather -- Chaotic cold accretion across the meso-scale: Variability and kinematics
University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学）；Universidad de Santiago de Chile（智利圣地亚哥大学）；INAF – Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；University of the Witwatersrand（威特沃特斯兰德大学）；Universität Hamburg（汉堡大学）
BlackHoleWeather -- Chaotic cold accretion across the meso-scale: Morphology and thermodynamics
University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学）；Universidad de Santiago de Chile（智利圣地亚哥大学）；INAF – Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；University of the Witwatersrand（威特沃特斯兰德大学）；Universität Hamburg（汉堡大学）
Wind-fed Supermassive Black Hole Accretion in the Ultracompact Dwarf Galaxy M60-UCD1
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（南京大学现代天文与天体物理教育部重点实验室）；Institute of Science and Technology for Deep Space Exploration, Suzhou Campus, Nanjing University（南京大学苏州校区深空探测研究院）
JWST Confirmation of a Runaway Supermassive Black Hole via its Supersonic Bow Shock
Yale University（耶鲁大学）；Dragonfly Focused Research Organization（龙卷风重点研究机构）；Harvard-Smithsonian Center for Astrophysics（哈佛-史密森尼天体物理中心）；University of California, Santa Barbara（加州大学圣塔芭芭拉分校）；University of Toronto（多伦多大学）；Tel Aviv University（特拉维夫大学）；San José State University（圣何塞州立大学）；University of California Santa Cruz（加州大学圣克鲁兹分校）
BlackHoleWeather -- Jet-regulated chaotic cold accretion across the meso scale: Morphology and thermodynamics
University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学）；Universidad de Santiago de Chile（圣地亚哥智利大学）；CIRAS, Universidad de Santiago de Chile（圣地亚哥智利大学 CIRAS）；INAF – Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；Science and Technology Institute, Universities Space Research Association（大学空间研究协会科学与技术学院）；Massachusetts Institute of Technology（麻省理工学院）
BlackHoleWeather -- Jet-regulated chaotic cold accretion across the meso scale: Variability and kinematics
University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学）；Universidad de Santiago de Chile（智利圣地亚哥大学）；CIRAS, Universidad de Santiago de Chile（智利圣地亚哥大学 CIRAS）；INAF – Astronomical Observatory of Rome（意大利国家天体物理研究所罗马天文台）；Universidad Diego Portales（迭戈帕托莱斯大学）；NASA Ames Research Center（美国宇航局艾姆斯研究中心）
Mapping Gas Accretion and Stellar Kinematics to Sub-kiloparsec Scales in NGC 4696 with JWST/NIRSpec
Université de Montréal（蒙特利尔大学）；Massachusetts Institute of Technology（麻省理工学院）；University of Michigan（密歇根大学）；Universidad Nacional Autónoma de México（墨西哥国立自治大学）；University of Alabama in Huntsville（阿拉巴马大学亨茨维尔分校）；University of Portsmouth（朴次茅斯大学）
