One of the most pressing questions in cosmology is how the black holes (BHs) powering quasars at high redshift grow to supermassive scales within a billion years of the Big Bang. Here we show that sustained super-Eddington accretion can be achieved for BHs with Eddington fractions $f_{\rm Edd}$ > 2/$ε$, where $ε$ is the efficiency with which radiation is generated in the accretion process. In this regime, the radiation carries too little momentum to halt the accretion flow and the infalling gas traps the radiation. The BH growth then proceeds unimpeded until the gas supply is exhausted, in contrast to accretion at lower rates which is limited by the radiation generated in the accretion process. The large gas supply available in massive high-redshift quasar host galaxies may be readily accreted onto seed BHs via this supply-limited mode of accretion, providing an explanation for how such supermassive BHs are assembled in the early universe. This sustained super-Eddington growth may also explain the short lifetimes inferred for the H II regions surrounding high-redshift quasars, if the bulk of the BH growth occurs without the associated radiation escaping to ionize the intergalactic medium. It furthermore implies that a population of obscured rapidly growing BHs may be difficult to detect, perhaps explaining why so few quasars with Eddington fractions higher than a few have been observed. Finally, this simple condition for sustained super-Eddington growth can easily be implemented in cosmological simulations which can be used to assess in which environments it occurs.
The role of major mergers in triggering super-Eddington accretion
Dipartimento di Fisica, “Sapienza” Università di Roma（罗马大学物理系）；INAF, Osservatorio Astronomico di Roma（罗马天文台）；INFN, Sezione Roma1（罗马第一国家核物理研究所）；Sapienza School for Advanced Studies（萨皮恩扎高等研究学院）；Como Lake Center for Astrophysics, DiSAT, Università degli Studi dell’Insubria（因苏布里亚大学迪萨特科莫湖天体物理学中心）；INFN, Sezione di Milano-Bicocca（米兰比可卡国家核物理研究所）；INAF, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（博洛尼亚空间天体物理学与科学天文台）
A novel sub-grid model for super-Eddington accretion of spinning black holes in galaxy-scale simulations
ETH Zürich（苏黎世联邦理工学院）；University of Oxford（牛津大学）；University of Zurich（苏黎世大学）；University of Geneva（日内瓦大学）；Università degli Studi dell’Insubria（因斯布鲁克大学）；Ludwig-Maximilians-Universität München（慕尼黑大学）
Three-Dimensional General Relativistic Radiation Magnetohydrodynamical Simulation of Super-Eddington Accretion, using a new code HARMRAD with M1 Closure
Super-Eddington Little Blue Dots May Reionize Helium Too Early
School of Earth and Space Exploration, Arizona State University（亚利桑那州立大学地球与空间探索学院）；Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Department of Physics and Astronomy, University of California, Riverside（加州大学河滨分校物理与天文学系）
Slowing down of cosmic growth of supermassive black holes: Theoretical prediction of the Eddington ratio distribution
本文用星系形成的半解析模型给出了宽红移范围（0 < z < 8）内超大质量黑洞的爱丁顿比分布。在低红移时，这个分布与观测估计大致一致。我们发现，在较高的红移的黑洞的增长率更有可能超过爱丁顿极限，因为在较高的红移的主机星系的典型气体分数较高。我们还发现，对于质量较小的超大质量黑洞，超爱丁顿增长更为普遍，支持了超大质量黑洞是通过超爱丁顿吸积形成的观点.这些结果表明了超大质量黑洞宇宙生长的“减速”：具有较高爱丁顿比的超大质量黑洞的生长在较高的红移处达到峰值。我们还显示了样本选择的爱丁顿比分布函数的形状上的效果，并发现，浅的观测将错过活动星系核，不仅更小，而且更高的爱丁顿比。
Formation of supermassive black holes (BHs) remains a theoretical challenge. In many models, especially beginning from stellar relic "seeds," this requires sustained super-Eddington accretion. While studies have shown BHs can violate the Eddington limit on accretion disk scales given sufficient "fueling" from larger scales, what remains unclear is whether or not BHs can actually capture sufficient gas from their surrounding ISM. We explore this in a suite of multi-physics high-resolution simulations of BH growth in magnetized, star-forming dense gas complexes including dynamical stellar feedba…
Super-Eddington accretion is one scenario that may explain the rapid assembly of $\sim 10^9\rm\, M_\odot$ supermassive black holes (BHs) within the first billion year of the Universe. This critical regime is associated with radiatively inefficient accretion and accompanied by powerful outflows in the form of winds and jets. By means of hydrodynamical simulations of BH evolution in an isolated galaxy and its host halo with 12 pc resolution, we investigate how super-Eddington feedback affects the mass growth of the BH. It is shown that super-Eddington feedback efficiently prevents BH growth with…
Super- and sub-Eddington accreting massive black holes: A comparison of slim and thin accretion discs through study of the spectral energy distribution
By performing three-dimensional hydrodynamical simulations of a galaxy in an isolated dark matter halo, we follow the evolution of the spin parameter $a$ of a black hole (BH) undergoing super-Eddington phases throughout its growth. This regime, suspected to be accompanied by powerful jet outflows, is expected to decrease the BH spin magnitude. We combine super-Eddington accretion with sub-Eddington phases (quasar and radio modes) and follow the BH spin evolution. Due to the low frequency of super-Eddington episodes, relativistic jets in this regime are not able to decrease the magnitude of the…
We present the first systematic broad-band X-ray study of super-Eddington accretion onto SMBHs with simultaneous {\it NuSTAR} and {\it XMM-Newton} or {\it Swift}/XRT observations of a sample of 8 super-Eddington accreting AGN with Eddington ratio $1<λ_{\rm Edd}<426$. We find that the SEAMBHs show a steep primary continuum slope as expected for sources accreting in the super Eddington regime, mostly dominated by relativistic reflection. The Iron K$α$ emission lines of the sources of our sample show relativistic broadening. In addition the equivalent widths of the narrow components of the Iron K…
We present a systematic X-ray and multiwavelength study of a sample of 47 active galactic nuclei (AGNs) with reverberation-mapping measurements. This sample includes 21 super-Eddington accreting AGNs and 26 sub-Eddington accreting AGNs. Using high-state observations with simultaneous X-ray and UV/optical measurements, we investigate whether super-Eddington accreting AGNs exhibit different accretion disk-corona connections compared to sub-Eddington accreting AGNs. We find tight correlations between the X-ray-to-UV/optical spectral slope parameter ($α_{\rm OX}$) and the monochromatic luminosity …
Propagation and dynamics of electromagnetic vortex solitons have been studied in the electron positron ion plasmas of super-Eddington active galactic nuclei (AGN). Existence and stability of such structures is demonstrated for highly transparent AGN plasma media. Possible implications of dynamical features and corresponding observational signatures are discussed.
X-ray fluorescence from super-Eddington accreting black holes
X射线混响已被证明是一种强有力的工具，能够探测致密物体周围吸积盘的最内部区域。目前的理论研究通常假设圆盘在几何上是薄的，光学上是厚的，并且以开普勒速度运行。因此，这些模型不能适用于系统的超爱丁顿吸积发生，因为薄盘近似失败，在这种吸积制度。此外，国家的最先进的数值模拟表明，光学厚风发射的超级爱丁顿吸积盘，从而改变了反射几何显着从薄盘图片。我们进行了理论研究这一主题的重点是铁K $α$荧光线产生的超爱丁顿磁盘，并表明，他们的线轮廓形状的漏斗几何形状和风加速度。我们还系统地比较了Fe线的轮廓从超爱丁顿厚磁盘薄磁盘，并发现前者更蓝移和对称的形状。这些结果与观测到的Fe K $α$线一致，该线来自喷射潮汐破裂事件Swift J1644，在该事件中，恒星碎片形成了瞬态的超爱丁顿吸积盘。因此，仔细分析的Fe K $α$线轮廓可以用来识别系统进行超爱丁顿吸积。
Anisotropic Radiation in Super-Eddington Active Galactic Nuclei: The Responsivity of Broad-Line Regions to Continuum Variability
State Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（高能物理研究所粒子天体物理国家重点实验室）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）
Rest-frame Optical Spectroscopy of $z \sim 2$ Quasars with Steep Hard X-ray Spectral Shapes: X-ray Selection of Super-Eddington Accretion and Verification
X-ray reverberation is a powerful technique which maps out the structure of the inner regions of accretion disks around black holes using the echoes of the coronal emission reflected by the disk. While the theory of X-ray reverberation has been developed almost exclusively for standard thin disks, recently reverberation lags have been observed from likely super-Eddington accretion sources such as the jetted tidal disruption event Swift J1644+57. In this paper, we extend X-ray reverberation studies into the super-Eddington accretion regime, focusing on investigating the lags in the Fe Kα line r…
The importance of super-Eddington black hole accretion for the emergence of massive quiescent galaxies at high redshift
Institute for Computational Cosmology, Department of Physics, University of Durham（达勒姆大学物理系计算宇宙学研究所）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；Lorentz Institute for Theoretical Physics, Leiden University（莱顿大学洛伦兹理论物理研究所）；Department of Astrophysics, University of Vienna（维也纳大学天体物理学系）
We perform the first three-dimensional radiation hydrodynamical simulations that investigate the growth of intermediate-mass BHs (IMBHs) embedded in massive self-gravitating, dusty nuclear accretion disks. We explore the dependence of mass accretion efficiency on the gas metallicity $Z$ and mass injection at super-Eddington accretion rates from the outer galactic disk $\dot{M}_{\rm in}$, and find that the central BH can be fed at rates exceeding the Eddington rate only when the dusty disk becomes sufficiently optically thick to ionizing radiation. In this case, mass outflows from the disk owin…
We study stellar and black hole mass assembly in a sample of 42 infrared-luminous galaxy mergers at z<0.3 by combining results from radiative transfer modelling with archival measures of molecular gas and black hole mass. The ratios of stellar mass, molecular gas mass, and black hole mass to each other are consistent with those of massive gas-rich galaxies at z<0.3. The advanced mergers may show increased black hole mass to stellar mass ratios, consistent with the transition from AGN to ellipticals and implying substantial black hole mass growth over the course of the merger. Star formation ra…
We present measurements of black hole masses and Eddington ratios for a sample of 38 bright (M$_{1450}$ < -24.4 mag) quasars at 5.8 < z < 7.5, derived from VLT/X-shooter near-IR spectroscopy of their broad CIV and MgII emission lines. The black hole masses (on average M$_{BH}$ ~ 4.6 x 10$^9$ M$_{\odot}$) and accretion rates (with Eddington ratios ranging between 0.1 and 1.0) are broadly consistent with that of similarly luminous 0.3 < z < 2.3 quasars, but there is evidence for a mild increase in the median Eddington ratio going towards z > 6. Combined with deep ALMA observations of the [CII] 1…
The Infrared Medium-deep Survey. IV. Low Eddington Ratio of A Faint Quasar at $z\sim6$: Not Every Supermassive Black Hole is Growing Fast in the Early Universe
Tidal disruption events (TDEs) around super massive black holes (SMBHs) are a potential laboratory to study super-Eddington accretion disks and sometimes result in powerful jets or outflows which may shine in the radio and sub millimeter bands. In this work, we model the thermal synchrotron emission of jets from general relativistic radiation magneto-hydrodynamics (GRRMHD) simulations of a BH accretion disk/jet system which assumes the TDE resulted in a magnetized accretion disk around a BH accreting at $\sim 12-25$ times the Eddington accretion rate. Through synthetic observations with the Ne…
We perform non-hydrodynamical 2.5D simulations to study the dynamics of material above accretion disk based on the disk radiation pressure acting on dust. We assume a super-accreting underlying disk with the accretion rate of 10 times the Eddington rate with central black hole mass ranging from $10^7$ up to $10^9 M_{\odot}$. Such high accretion rates are characteristic for extreme sources. We show that for high accretors radiatively dust-driving mechanism based on FRADO model always leads to a massive outflow from the disk surface, and the failed wind develops only at larger radii. The outflow…
A Super-Eddington, Lensing-Magnified Quasar at $z=5.07$ observed with JWST
Massachusetts Institute of Technology（麻省理工学院）；University of Arizona（亚利桑那大学）；MIT Kavli Institute for Astrophysics and Space Research（麻省理工学院卡弗里天体物理与空间研究所）；University of Michigan（密歇根大学）
Radio emission from the high- and super-Eddington accreting active galactic nuclei (AGNs) has various origins: a persistent jet, the magnetized corona and the wind-like outflows. It is now still unclear which is the leading mechanism responsible for the observed radio emission and how the radio emission is related to other characteristic parameters such as the Eddington ratio and black hole mass. In this paper, we present the 5 GHz Very Large Array (VLA) observational results of a sample of 25 extremely high Eddington accreting supermassive black holes (EESBHs, the Eddington ratio close to or …
JWST Spectroscopic View of a Rapidly Growing Dust-obscured Quasar at $z \sim 4$: Effect of Dust Extinction Correction on Black Hole Mass and Eddington Ratio Estimation
Episodic super-Eddington accretion as a clue to Overmassive Black Holes in the early Universe
Institute for Astronomy, University of Edinburgh（爱丁堡大学天体物理研究所）；Como Lake Center for Astrophysics, DiSAT, Università degli Studi dell’Insubria（因苏布里亚大学DiSAT科莫湖天体物理学中心）；INAF/Osservatorio Astronomico di Roma（罗马天文台（意大利国家天体物理研究所））；INFN, Sezione Roma1, Dipartimento di Fisica, “Sapienza” Università di Roma（罗马第一大学物理系意大利国家核物理研究院罗马一分部）；Dipartimento di Fisica, “Sapienza” Università di Roma（罗马第一大学物理系）；Sapienza School for Advanced Studies（罗马第一大学高等研究学院）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）
