Supermassive stars have been proposed as the progenitors of the massive ($\sim 10^{9}\,\rm{M}_{\odot}$) quasars observed at $z\sim7$. Prospects for directly detecting supermassive stars with next-generation facilities depend critically on their intrinsic lifetimes, as well as their formation rates. We use the 1D stellar evolution code Kepler to explore the theoretical limiting case of zero-metallicity, non-rotating stars, formed monolithically with initial masses between $10\,\rm{kM}_{\odot}$ and $190\,\rm{kM}_{\odot}$. We find that stars born with masses between $\sim60\,\rm{kM}_{\odot}$ and $\sim150\,\rm{kM}_{\odot}$ collapse at the end of the main sequence, burning stably for $\sim1.5\,\rm{Myr}$. More massive stars collapse directly through the general relativistic instability after only a thermal timescale of $\sim3\,\rm{kyr}$--$4\,\rm{kyr}$. The expected difficulty in producing such massive, thermally-relaxed objects, together with recent results for currently preferred rapidly-accreting formation models, suggests that such ``truly direct'' or ``dark'' collapses may not be typical for supermassive objects in the early Universe. We close by discussing the evolution of supermassive stars in the broader context of massive primordial stellar evolution and the possibility of supermassive stellar explosions.
Supermassive stars are Population III stars with masses exceeding $10^4\,M_{\odot}$ that could be the progenitors of the first supermassive black holes. Their interiors are in a regime where radiation pressure dominates the equation of state. In this work, we use the explicit gas dynamics code PPMstar to simulate the hydrogen-burning core of a $10^4\,M_{\odot}$ supermassive main-sequence star. These are the first 3D hydrodynamics simulations of core convection in supermassive stars. We perform a series of ten simulations at different heating rates and on Cartesian grids with resolutions of $76…
Supermassive primordial stars with masses exceeding $\sim10^5\,M_{\odot}$ that form in atomically cooled halos are the leading candidates for the origin of high-redshift quasars with $z>6$. Recent numerical simulations, however, find that multiple accretion disks can form within a halo, each of which can host a supermassive star. Tidal interactions between the disks can gravitationally torque gas onto their respective stars and alter their evolution. Later, when two satellite disks collide, the two stars can come into close proximity. This may induce additional mass exchange between them. We i…
Major mergers of gas-rich galaxies provide promising conditions for the formation of supermassive black holes (SMBHs; $\gtrsim10^5$ M$_\odot$) by direct collapse because they can trigger mass inflows as high as $10^4-10^5$ M$_\odot$ yr$^{-1}$ on sub-parsec scales. However, the channel of SMBH formation in this case, either dark collapse (direct collapse without prior stellar phase) or supermassive star (SMS; $\gtrsim10^4$ M$_\odot$), remains unknown. Here, we investigate the limit in accretion rate up to which stars can maintain hydrostatic equilibrium. We compute hydrostatic models of SMSs ac…
Supermassive stars (SMSs), with masses $>10^5$ M$_\odot$, have been proposed as the possible progenitors of the most extreme supermassive black holes observed at redshifts $z>6-7$. In this scenario ('direct collapse'), a SMS accretes at rates $>0.1$ M$_\odot$ yr$^{-1}$ until it collapses to a black hole via the general-relativistic (GR) instability. Rotation plays a crucial role in the formation of such supermassive black hole seeds. The centrifugal barrier appears as particularly strong in this extreme case of star formation. Moreover, rotation impacts sensitively the stability of SMSs agains…
Supermassive stars forming at $z \sim$ 15 - 20 are one of the leading contenders for the origin of the first quasars, over 200 of which have now been discovered at $z >$ 6. These stars likely form in pristine, atomically cooled haloes immersed in strong Lyman-Werner UV backgrounds or in highly supersonic baryon streaming flows. Atomic cooling triggers catastrophic baryon collapse capable of building up stars at rates of up to $\sim$1 M$_{\odot}$ yr$^{-1}$. Here we examine the evolution of supermassive stars with a much larger and finer grid of accretion rates than in previous studies with the …
Direct collapse black hole (DCBH) formation with mass $\gtrsim 10^{5}~M_{\odot}$ is a promising scenario for the origin of high-redshift supermassive black holes. It has usually been supposed that the DCBH can only form in the primordial gas since the metal enrichment enhances the cooling ability and causes the fragmentation into smaller pieces. What actually happens in such an environment, however, has not been explored in detail. Here, we study the impact of the metal enrichment on the clouds, conducting hydrodynamical simulations to follow the cloud evolution in cases with different degree …
The close neighbourhood of a supermassive black hole contains not only accreting gas and dust, but also stellar-sized objects like stars, stellar-mass black holes, neutron stars, and dust-enshrouded objects that altogether form a dense nuclear star-cluster. These objects interact with the accreting medium and they perturb the otherwise quasi-stationary configuration of the accretion flow. We investigate how the passages of a star can influence the black hole gaseous environment with GRMHD 2D and 3D simulations. We focus on the changes in the accretion rate and the associated emergence of outfl…
Supermassive primordial stars are suspected to be the progenitors of the most massive quasars at z~6. Previous studies of such stars were either unable to resolve hydrodynamical timescales or considered stars in isolation, not in the extreme accretion flows in which they actually form. Therefore, they could not self-consistently predict their final masses at collapse, or those of the resulting supermassive black hole seeds, but rather invoked comparison to simple polytropic models. Here, we systematically examine the birth, evolution and collapse of accreting non-rotating supermassive stars un…
Supermassive stars (SMS; ~ 10^5 M_sun) formed from metal-free gas in the early Universe attract attention as progenitors of supermassive black holes observed at high redshifts. To form SMSs by accretion, central protostars must accrete at as high rates as ~ 0.1-1 M_sun/yr. Such protostars have very extended structures with bloated envelopes, like super-giant stars, and are called super-giant protostars (SGPSs). Under the assumption of hydrostatic equilibrium, SGPSs have density inverted layers, where the luminosity becomes locally super-Eddington, near the surface. If the envelope matter is al…
A strong nuclear kilomaser, W1, has been found in the nearby galaxy NGC 253, associated with a forming super star cluster. Kilomasers could arise from the accretion disc around supermassive stars (>10^3 Msun), hypothetical objects that have been proposed as polluters responsible for the chemical peculiarities in globular clusters. The supermassive stars would form via runaway collisions, simultaneously with the cluster. Their discs are perturbed by stellar flybys, inspiralling and colliding stars. This raises the question if an accretion disc would at all be able to survive in such a dynamic e…
The "direct collapse" scenario has emerged as a promising evolutionary track for the formation of supermassive black holes early in the Universe. In an idealized version of such a scenario, a uniformly rotating supermassive star spinning at the mass-shedding (Keplerian) limit collapses gravitationally after it reaches a critical configuration. Under the assumption that the gas is dominated by radiation pressure, this critical configuration is characterized by unique values of the dimensionless parameters $J/M^2$ and $R_p/M$, where $J$ is the angular momentum, $R_p$ the polar radius, and $M$ th…
A dust-free hierarchically nested supermassive-star model for James Webb Space Telescope Little Red Dots
Universitat Politècnica de València（瓦伦西亚理工大学）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；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）
The formation of supermassive stars is believed to be an essential intermediate step for the formation of the massive black hole seeds that become the supermassive black holes powering the quasars observed in the early Universe. Numerical simulations have shown that supermassive stars can form in atomic-cooling halos when protostars reach accretion rates higher than $\sim10^{-2}$ M$_\odot$ yr$^{-1}$ and fragmentation is suppressed on pc scales. It is however still uncertain if a supermassive star still emerges when fragmentation occurs at smaller scales and a cluster of stars is formed instead…
We analyze the outcome of the interaction between a stellar binary and a supermassive black hole binary (SMBHB) by performing a large number of gravitational scattering experiments. Most of the encounters result in either the ejection of an intact binary or the ejection of two individual stars following the tidal breakup of the binary. However, tidal disruption events (TDEs) and mergers constitute a few percent of the outcomes, and double, temporally distinct TDEs (i.e., separated by at least one orbit of the supermassive black hole binary) occur at the percent level. We also demonstrate that …
Supermassive black holes are a key ingredient of galaxy evolution. However, their origin is still highly debated. In one of the leading formation scenarios, a black hole of $\sim100$ M$_{\odot}$ results from the collapse of the inner core of a supermassive star ($\gtrsim 10^{4-5}$ M$_{\odot}$), created by the rapid accumulation ($\gtrsim 0.1 $ M$_{\odot}$ yr$^{-1}$) of pristine gas at the centre of newly formed galaxies at $z\sim 15$. The subsequent evolution is still speculative: the remaining gas in the supermassive star can either directly plunge into the nascent black hole, or part of it c…
The origin of supermassive black holes (with $\gtrsim\!10^9\,M_{\odot}$) in the early universe (redshift $z \sim 7$) remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We focus on the magnetic effects on star formation that occurs in an atomic-cooling gas cloud. Using a set of three-dimensional magnetohydrodynamic (MHD) simulations, we investigate the star formation process in the magnetized atomic-cooling gas cloud with different initial magnetic field s…
Supermassive primordial stars in hot, atomically-cooling haloes at $z \sim$ 15 - 20 may have given birth to the first quasars in the universe. Most simulations of these rapidly accreting stars suggest that they are red, cool hypergiants, but more recent models indicate that some may have been bluer and hotter, with surface temperatures of 20,000 - 40,000 K. These stars have spectral features that are quite distinct from those of cooler stars and may have different detection limits in the near infrared (NIR) today. Here, we present spectra and AB magnitudes for hot, blue supermassive primordial…
We discuss the formation and evolution of systems comprised of a low-mass ($M_\star \lesssim 4 \, \rm M_\odot$) main sequence star, orbiting a $10^5-10^7 \, \rm M_\odot$ supermassive black hole with an orbital period of order $\sim$hours, and a mild eccentricity ($e\approx0.1-0.2$), episodically shedding mass at each pericenter passage. We argue that the resulting mass transfer is likely unstable, with Roche lobe overflow initially driven by gravitational wave emission, but then being accelerated by the star's expansion in response to its mass loss, undergoing a runaway process. We show that s…
We show results from the radiation hydrodynamics (RHD) simulations of tidal disruption of a star on a parabolic orbit by a supermassive black hole (SMBH) based on a three-dimensional smoothed particle hydrodynamics code with radiative transfer. We find that such a tidally disrupted star fragment and form clumps soon after its tidal disruption. The fragmentation results from the endothermic processes of ionization and dissociation that reduce the gas pressure, leading to local gravitational collapse. Radiative cooling is less effective because the stellar debris is still highly optically thick …
Context. Machine-Learning (ML) solves problems by learning patterns from data, with limited or no human guidance. In Astronomy, it is mainly applied to large observational datasets, e.g. for morphological galaxy classification. Aims. We apply ML to gravitational N-body simulations of star clusters that are either formed by merging two progenitors or evolved in isolation, planning to later identify Globular Clusters (GCs) that may have a history of merging from observational data. Methods. We create mock-observations from simulated GCs, from which we measure a set of parameters (also called fea…
Tidal disruption events (TDEs) provide a unique opportunity to probe the stellar populations around supermassive black holes (SMBHs). By combining light curve modeling with spectral line information and knowledge about the stellar populations in the host galaxies, we are able to constrain the properties of the disrupted star for three TDEs. The TDEs in our sample have UV spectra, and measurements of the UV N III to C III line ratios enabled estimates of the nitrogen-to-carbon abundance ratios for these events. We show that the measured nitrogen line widths are consistent with originating from …
Primordial supermassive stars (SMSs) formed in atomic-cooling halos at z ~ 15 - 20 are leading candidates for the seeds of the first quasars. Past numerical studies of the evolution of SMSs have typically assumed constant accretion rates rather than the highly variable flows in which they form. We model the evolution of SMSs in the cosmological flows that create them using the Kepler stellar evolution and implicit hydrodynamics code. We find that they reach masses of 1 - 2 x $10^5 M_{\odot}$ before undergoing direct-collapse to black holes (DCBHs) during or at the end of their main-sequence hy…
Supermassive black holes (SMBHs) in galactic nuclei can eject hypervelocity stars (HVSs). Using restricted three-body integrations, we study the properties of stars ejected by circular, binary SMBHs as a function of their mass ratios $q = M_2 / M_1$ and separations $a$, focusing on the stellar velocity and angular distributions. We find that the ejection probability is an increasing function of $q$ and $a$, and that the mean ejected velocity scales with $q$ and $a$ similar to previous work but with modified scaling constants. Binary SMBHs tend to eject their fastest stars toward the binary orb…
Approximately two hundred supermassive black holes (SMBHs) have been discovered within the first $\sim$Gyr after the Big Bang. One pathway for the formation of SMBHs is through the collapse of supermassive stars (SMSs). A possible obstacle to this scenario is that the collapsing gas fragments and forms a cluster of main-sequence stars. Here we raise the possibility that stellar collisions may be sufficiently frequent and energetic to inhibit the contraction of the massive protostar, avoiding strong UV radiation driven outflows, and allowing it to continue growing into an SMS. We investigate th…
Stars that plunge into the center of a galaxy are tidally perturbed by a supermassive black hole (SMBH), with closer encounters resulting in larger perturbations. Exciting these tides comes at the expense of the star's orbital energy, which leads to the naive conclusion that a smaller pericenter (i.e., a closer encounter between the star and SMBH) always yields a more tightly bound star to the SMBH. However, once the pericenter distance is small enough that the star is partially disrupted, morphological asymmetries in the mass lost by the star can yield an \emph{increase} in the orbital energy…
The formation of supermassive stars (SMSs) is a possible pathway to seed supermassive black holes in the early universe. This chapter summarizes recent theoretical efforts to understand their evolution, highlighting effects of very rapid accretion at the rates of $\dot{M}_* \gtrsim 0.1~$M$_\odot$ yr$^{-1}$. Stellar evolution calculations predict that such an accreting SMS has a characteristic feature, i.e., a very large radius that monotonically increases as the stellar mass increases. The radius exceeds $7000$ R$_\odot$ (or $30$ AU) after the star accretes the gas of more than $10^3$ M$_\odot…
Supermassive black holes are found at the centre of massive galaxies. During the growth of these black holes they light up to become visible as active galactic nuclei (AGN) and release extraordinary amounts of energy across the electromagnetic spectrum. This energy is widely believed to regulate the rate of star formation in the black holes' host galaxies via so-called "AGN feedback". However, the details of how and when this occurs remains uncertain from both an observational and theoretical perspective. I review some of the observational results and discuss possible observational signatures …
Stars with short orbital periods at the center of our galaxy offer a powerful and unique probe of a supermassive black hole. Over the past 17 years, the W. M. Keck Observatory has been used to image the Galactic center at the highest angular resolution possible today. By adding to this data set and advancing methodologies, we have detected S0-102, a star orbiting our galaxy's supermassive black hole with a period of just 11.5 years. S0-102 doubles the number of stars with full phase coverage and periods less than 20 years. It thereby provides the opportunity with future measurements to resolve…
Some ultra-compact dwarf galaxies (UCDs) have elevated observed dynamical V-band mass-to-light ($M/L_{\rm V}$) ratios with respect to what is expected from their stellar populations assuming a canonical initial mass function (IMF). Observations have also revealed the presence of a compact dark object in the centers of several UCDs, having a mass of a few to 15\% of the present-day stellar mass of the UCD. This central mass concentration has typically been interpreted as a super-massive black hole, but can in principle also be a sub-cluster of stellar remnants. We explore the following two form…
We consider the problem of star consumption by supermassive black holes in non-spherical (axisymmetric, triaxial) galactic nuclei. We review the previous studies of the loss-cone problem and present a novel simulation method which allows to separate out the collisional (relaxation-related) and collisionless (related to non-conservation of angular momentum) processes and determine their relative importance for the capture rates in different geometries. We show that for black holes more massive than 10^7 Msun, the enhancement of capture rate in non-spherical galaxies is substantial, with even mo…
We propose a novel source of gravitational wave emission: the inspirals of compact fragments inside primordial supermassive stars (SMSs). Such systems are thought to be an essential channel in the as-yet little understood formation of supermassive black holes (SMBHs). One model suggests that high accretion rates of $0.1$-1 M$_\odot$/yr attainable in atomically-cooled primordial halos can lead to the formation of a nuclear-burning SMS. This will ultimately undergo collapse through a relativistic instability, leaving a massive BH remnant. Recent simulations suggest that supermassive stars rarely…
Formation of supermassive stars (SMSs) with mass ~10^4 Msun is a promising pathway to seed the formation of supermassive black holes in the early universe. The so-called direct-collapse (DC) model postulates that such an SMS forms in a hot gas cloud irradiated by a nearby star-forming galaxy. We study the DC SMS formation in a fully cosmological context using three-dimensional radiation hydrodynamics simulations. We initialize our simulations using the outputs of the cosmological simulation of Chon et al. (2016), where two DC gas clouds are identified. The long-term evolution over a hundred th…
An enhanced rate of stellar tidal disruption events (TDEs) may be an important characteristic of supermassive black hole (SMBH) binaries at close separations. Here we study the evolution of the distribution of stars around a SMBH binary due to the eccentric Kozai-Lidov (EKL) mechanism, including octupole effects and apsidal precession caused by the stellar mass distribution and general relativity. We identify a region around one of the SMBHs in the binary where the EKL mechanism drives stars to high eccentricities, which ultimately causes the stars to either scatter off the second SMBH or get …
This article provides a summary of XMM-Newton highlights on stellar tidal disruption events. First found with ROSAT, ongoing and upcoming sky surveys will detect these events in the 1000s. In X- rays, tidal disruption events (TDEs) provide us with powerful new probes of accretion physics under extreme conditions and on short timescales and of relativistic effects near the SMBH, of the formation and evolution of disk winds near or above the Eddington limit, and of the processes of high-energy emission from newly launched radio jets. TDEs serve as signposts of the presence of dormant, single bla…
The collapse of supermassive primordial stars in hot, atomically-cooled halos may have given birth to the first quasars at $z \sim$ 15 - 20. Recent numerical simulations of these rapidly accreting stars reveal that they are cool, red hypergiants shrouded by dense envelopes of pristine atomically-cooled gas at 6,000 - 8,000 K, with luminosities $L$ $\gtrsim$ 10$^{10}$ L$_{\odot}$. Could such luminous but cool objects be detected as the first stage of quasar formation in future near infrared (NIR) surveys? We have now calculated the spectra of supermassive primordial stars in their birth envelop…
Supermassive black hole binaries (SMBHBs) are the products of frequent galaxy mergers. The coalescence of the SMBHBs is a distinct source of gravitational wave (GW) radiation. The detections of the strong GW radiation and their possible electromagnetic counterparts are essential. Numerical relativity suggests that the post-merger supermassive black hole (SMBH) gets a kick velocity up to 4000 km/s due to the anisotropic GW radiations. Here we investigate the dynamical co-evolution and interaction of the recoiling SMBHs and their galactic stellar environments with one million direct N-body simul…
Tidal Disruption of stars by supermassive central black holes from dense rotating star clusters is modelled by high-accuracy direct N-body simulation. As in a previous paper on spherical star clusters we study the time evolution of the stellar tidal disruption rate and the origin of tidally disrupted stars, now according to several classes of orbits which only occur in axisymmetric systems (short axis tube and saucer). Compared with that in spherical systems, we found a higher TD rate in axisymmetric systems. The enhancement can be explained by an enlarged loss-cone in phase space which is rai…
ESO 243-49 is a high-mass (circular velocity $v_{\rm c}\approx200\,{\rm km\,s^{-1}}$) edge-on S0 galaxy in the Abell 2877 cluster at a distance of $\sim95\,{\rm Mpc}$. To elucidate the origin of its thick disc, we use MUSE science verification data to study its kinematics and stellar populations. The thick disc emits $\sim80\%$ of the light at heights in excess of $3.5^{\prime\prime}$ ($1.6\,{\rm kpc}$). The rotation velocities of its stars lag by $30-40\,{\rm km\,s^{-1}}$ compared to those in the thin disc, which is compatible with the asymmetric drift. The thick disc is found to be more meta…
Theoretical models and numerical simulations have established a framework of galaxy evolution in which galaxies merge and create dual supermassive black holes (with separations of one to ten kiloparsecs), which eventually sink into the centre of the merger remnant, emit gravitational waves and coalesce. The merger also triggers star formation and supermassive black hole growth, and gas outflows regulate the stellar content. Although this theoretical picture is supported by recent observations of starburst-driven and supermassive black hole-driven outflows, it remains unclear how these outflows…
Supermassive black hole binaries (BHBs) are expected to be one of the most powerful sources of low-frequency gravitational waves (GWs) for future space-borne detectors. Prior to the GW emission stage, BHBs evolving in gas-poor nuclei shrink primarily through the slingshot ejection of stars approaching the BHB from sufficiently close distances. Here we address the possibility that the BHB shrinking rate is enhanced through the infall of a star cluster (SC) onto the BHB. We present the results of direct summation N-body simulations exploring different orbits for the SC infall, and we show that S…
The supermassive black hole (SMBH) with 4 millions solar mass inside the radio-source Sgr A* in our Galactic center is the nearest SMBH. Once the S stars with shorter period are observed, the relativistic precessions especially the Lense-Thirring one can be measured by astronomical observations at 10 micro-arcsecond ($μ$as) level in future. An interesting but so far no attended problem is that the SMBH has not only spin but also spin precession like the other objects in the universe. In this paper, we study the effect of such spin precession on the orbital precessions of orbiting stars. Our re…
We present a model for the evolution of supermassive protostars from their formation at $M_\star \simeq 0.1\,\text{M}_\odot$ until their growth to $M_\star \simeq 10^5\,\text{M}_\odot$. To calculate the initial properties of the object in the optically thick regime we follow two approaches: based on idealized thermodynamic considerations, and on a more detailed one-zone model. Both methods derive a similar value of $n_{\rm F} \simeq 2 \times 10^{17} \,\text{cm}^{-3}$ for the density of the object when opacity becomes important, i.e. the opacity limit. The subsequent evolution of the growing pr…
We investigate the formation of circumnuclear gas structures from the tidal disruption of molecular clouds in galactic nuclei, by means of smoothed particle hydrodynamics simulations. We model galactic nuclei as composed of a supermassive black hole (SMBH) and a nuclear star cluster (NSC) and consider different mass ratios between the two components. We find that the relative masses of the SMBH and the NSC have a deep impact on the morphology of the circumnuclear gas. Extended disks form only inside the sphere of influence of the SMBH. In contrast, compact rings naturally form outside the SMBH…
Supermassive stars (SMSs) with $\sim10^{4-5}~\mathrm{M}_{\odot}$ are candidate objects for the origin of supermassive black holes observed at redshift $z$>6. They are supposed to form in primordial-gas clouds that provide the central stars with gas at a high accretion rate, but their growth may be terminated in the middle due to the stellar ionizing radiation if the accretion is intermittent and its quiescent periods are longer than the Kelvin-Helmholtz (KH) timescales at the stellar surfaces. In this paper, we examine the role of the ionizing radiation feedback based on the accretion history …
Hypervelocity stars (HVSs) that are observed in the Galactic halo, are believed to be accelerated to large velocities by a process of tidal disruption of binary stars passing close to a supermassive black hole (SMBH) which resides in the center of the Galaxy. It is, however, still unclear, where these relatively young stars were born and which dynamical process pushed them to nearly radial orbits around the SMBH. In this paper we investigate the possibility that the young binaries originated from a thin eccentric disc, similar to the one observed in the Galactic center nowadays. By means of di…
We present a new analytical solution to the steady-state distribution of stars close to a central supermassive black hole of mass $M_{\bullet}$ in the center of a galaxy. Assuming a continuous mass function of the form $dN/dm \propto m^γ$, stars with a specific orbital energy $x = GM_{\bullet}/r - v^2/2$ are scattered primarily by stars of mass $m_{\rm d}(x) \propto x^{-5/(4γ+10)}$ that dominate the scattering of both lighter and heavier species at that energy. Stars of mass $m_{\rm d}(x)$ are exponentially rare at energies lower than $x$, and follow a density profile $n(x') \propto x'^{3/2}$ …
Supermassive stars born in pristine environments in the early Universe hold the promise of being the seeds for the supermassive black holes observed as high redshift quasars shortly after the epoch of reionisation. H$_2$ suppression is thought to be crucial in order to negate normal Population III star formation and allow high accretion rates to drive the formation of supermassive stars. Only in the cases where vigorous fragmentation is avoided will a monolithic collapse be successful giving rise to a single massive central object. We investigate the number of fragmentation sites formed in col…
The formation of supermassive black holes from Population III.1 seeds. IV. Self-regulated seeding from supermassive star ionizing feedback
Chalmers University of Technology（查尔姆斯理工大学）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；University of Modena & Reggio Emilia（摩德纳与雷焦艾米利亚大学）；University of Oxford（牛津大学）；University of Memphis（孟菲斯大学）；Center for Astrophysics, Harvard and Smithsonian（哈佛史密松天体物理中心）；Università degli Studi di Trieste（的里雅斯特大学）；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）；INFN, Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）
The empirical model of Lu et al. 2014a for the relation between star formation rate and halo mass growth is adopted to predict the classical bulge mass ($M_{\rm cb}$) - total stellar mass ($M_\star$) relation for central galaxies. The assumption that the supermassive black hole (SMBH) mass ($M_{\rm BH}$) is directly proportional to the classical bulge mass, with the proportionality given by that for massive galaxies, predicts a $M_{\rm BH}$ - $M_\star$ relation that matches well the observed relation for different types of galaxies. In particular, the model reproduces the strong transition at …
Possible Supermassive Dark Object Composed of Light Fermionic Gas with an Embedded Neutron Star Core
SDU-ANU Joint Science College, Shandong University（山东大学-澳国立大学联合学院）；School of Nuclear Science, Energy and Power Engineering, Shandong University（山东大学核科学与能源动力工程学院）
