We propose a new scenario for supermassive star (SMS;>10^5Msun) formation in shocked regions of colliding cold accretion flows near the centers of first galaxies. Recent numerical simulations indicate that assembly of a typical first galaxy with virial temperature (~10^4K) proceeds via cold and dense flows penetrating deep to the center, where the supersonic streams collide each other to develop a hot and dense (~10^4K, ~10^3/cc) shocked gas. The post-shock layer first cools by efficient Ly alpha emission and contracts isobarically until 8000K. Whether the layer continues the isobaric contraction depends on the density at this moment: if the density is high enough for collisionally exciting H2 rovibrational levels (>10^4/cc), enhanced H2 collisional dissociation suppresses the gas to cool further. In this case, the layer fragments into massive (>10^5Msun) clouds, which collapse isothermally (~8000K) by the Ly alpha cooling without subsequent fragmentation. As an outcome, SMSs are expected to form and evolve eventually to seeds of supermassive black holes (SMBH). By calculating thermal evolution of the post-shock gas, we delimit the range of post-shock conditions for the SMS formation, which can be expressed as: T>6000K/(n/10^4/cc) for n<10^4/cc and T>5000-6000K for n>10^4/cc, depending somewhat on initial ionization degree. We found that metal enrichment does not affect the above condition for metallicity below 10^-3Zsun if metals are in the gas phase, while condensation of several percent of metals into dust decreases this critical value of metallicity by an order of magnitude. Unlike the previously proposed scenario for SMS formation, which postulates extremely strong ultraviolet radiation to quench H2 cooling, our scenario naturally explains the SMBH seed formation in the assembly process of the first galaxies, even without such a strong radiation.
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）
Hot versus Cold: the Dichotomy in Spherical Accretion of Cooling Flows onto Supermassive Black Holes in Elliptical Galaxies, Galaxy Groups and Clusters
Self-regulated growth of supermassive black holes by a dual jet/heating AGN feedback mechanism: methods, tests and implications for cosmological simulations
Feeding compact bulges and supermassive black holes with low angular-momentum cosmic gas at high redshift
我们使用宇宙流体动力学模拟表明，一个显着的一部分气体在高红移罕见的大质量晕几乎径向下降到他们的中心在极短的时间尺度。这一过程导致了非常致密的膨胀的形成，其特定的角动量是5-30 $smaller than the average angular momentum of the baryons in the whole halo. Such low angular momentum originates both from segregation and effective cancellation when the gas flows to the centre of the halo along well defined cold filamentary streams. These filaments penetrate deep inside the halo and connect to the bulge from multiple rapidly changing directions. Structures falling in along the filaments (satellite galaxies) or formed by gravitational instabilities triggered by the inflow (star clusters)…
Early Supermassive Black Holes and Little Red Dots Require Free-Fall Growth
Department of Astronomy, University of Texas, Austin（德克萨斯大学奥斯汀分校天文学系）；Cosmic Frontier Center, The University of Texas, Austin（德克萨斯大学奥斯汀分校宇宙前沿中心）；Weinberg Institute for Theoretical Physics, University of Texas, Austin（德克萨斯大学奥斯汀分校温伯格理论物理研究所）
The background gas humming and multi-messenger transients of stalled supermassive black hole binaries
Universitat Politècnica de València（巴伦西亚理工大学）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；Dipartimento di Fisica e Astronomia “Galileo Galilei”, Univ. di Padova（帕多瓦大学伽利略·伽利莱物理与天文学系）；Fesenkov Astrophysical Institute（费森可夫天文物理研究所）
Signatures of Exploding Supermassive PopIII Stars at High Redshift in JWST, EUCLID and Roman Space Telescope
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；Institute for Cosmic Ray Research, The University of Tokyo（东京大学宇宙射线研究所）；Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理中心引力物理与量子信息研究中心）；Frontier Research Institute for Interdisciplinary Sciences, Tohoku University（东北大学前沿交叉科学研究所）；Astronomical Institute, Graduate School of Science, Tohoku University（东北大学理学研究科天文学系）
Centre for Space Research, North-West University（西北大学空间研究中心）；National Centre for Radio Astrophysics (NCRA), Tata Institute of Fundamental Research (TIFR)（塔塔基础研究院国家射电天文学中心）；National Institute for Theoretical and Computational Sciences (NITheCS)（理论与计算科学国立研究所）；Dayanand Science College（戴亚南德理学院）
