We present Chandra observations of 12 galaxies that contain supermassive black holes with dynamical mass measurements. Each galaxy was observed for 30 ksec and resulted in a total of 68 point source detections in the target galaxies including supermassive black hole sources, ultraluminous X-ray sources, and extragalactic X-ray binaries. Based on our fits of the X-ray spectra, we report fluxes, luminosities, Eddington ratios, and slope of the power-law spectrum. Normalized to the Eddington luminosity, the 2--10 keV band X-ray luminosities of the SMBH sources range from $10^{-8}$ to $10^{-6}$, and the power-law slopes are centered at $\sim2$ with a slight trend towards steeper (softer) slopes at smaller Eddington fractions, implying a change in the physical processes responsible for their emission at low accretion rates. We find 20 ULX candidates, of which six are likely ($>90%$ chance) to be true ULXs. The most promising ULX candidate has an isotropic luminosity in the 0.3--10 keV band of $1.0_{-0.3}^{+0.6} \times 10^{40}$ erg/s.
Extragalactic X-ray surveys over the past decade have dramatically improved understanding of the majority populations of active galactic nuclei (AGNs) over most of the history of the Universe. Here we briefly highlight some of the exciting discoveries about AGN demography, physics, and ecology with a focus on results from Chandra. We also discuss some key unresolved questions and future prospects.
Gas undergoing Bondi accretion onto a supermassive black hole (SMBH) becomes hotter toward smaller radii. We searched for this signature with a Chandra observation of the hot gas in NGC 3115, which optical observations show has a very massive SMBH. Our analysis suggests that we are resolving, for the first time, the accretion flow within the Bondi radius of an SMBH. We show that the temperature is rising toward the galaxy center as expected in all accretion models in which the black hole is gravitationally capturing the ambient gas. There is no hard central point source that could cause such a…
We present analysis of Chandra X-ray observations of seven quasars that were identified as candidate sub-parsec binary supermassive black hole (SMBH) systems in the Catalina Real-Time Transient Survey (CRTS) based on apparent periodicity in their optical light curves. Simulations predict close-separation accreting SMBH binaries will have different X-ray spectra than single accreting SMBHs, including harder or softer X-ray spectra, ripple-like profiles in the Fe K-$α$ line, and distinct peaks in the spectrum due to the separation of the accretion disk into a circumbinary disk and mini-disks aro…
The main idea of our research is to estimate the physical coalescence time of the double supermassive black hole (SMBH) system in the centre of NGC 6240 based on the X-ray observations from the Chandra space observatory. The spectra of the Northern and Southern nuclei were fitted by spectral models from Sherpa and both presented the narrow component of the Fe K$α$ emission line. It enabled us to apply the spectral model to these lines and to find relative offset $\approx0.02$ keV. The enclosed dynamical mass of the central region of NGC 6240 with radius 1 kpc was estimated $\approx 2.04\times …
Spin measurements of supermassive black holes (SMBHs) provide crucial constraints on the accretion processes that power active galactic nuclei (AGN), fuel outflows, and trigger black hole growth. However, spin measurements are mainly limited to a few dozen nearby sources for which high quality, high S/N spectra (e.g., from Chandra, XMM-Newton, Suzaku, NuSTAR) are available. Here we measure the average SMBH spin of $\sim$1900 AGN in the Chandra COSMOS-Legacy survey using spectral stacking analysis. We find broad Fe K$α$ line emission in the average COSMOS spectrum (Gaussian width $σ=0.27\pm0.05…
X-ray emission from quasars has been detected up to redshift $z=7.5$, although only limited to a few objects at $z>6.5$. In this work, we present new Chandra observations of five $z>6.5$ quasars. By combining with archival Chandra observations of six additional $z>6.5$ quasars, we perform a systematic analysis on the X-ray properties of these earliest accreting supermassive black holes (SMBHs). We measure the black hole masses, bolometric luminosities ($L_{\rm bol}$), Eddington ratios ($λ_{\rm Edd}$), emission line properties, and infrared luminosities ($L_{\rm IR}$) of these quasars using inf…
We study the X-ray variability properties of distant AGNs in the Chandra Deep Field-South region over 17 years, up to $z\sim 4$, and compare them with those predicted by models based on local samples. We use the results of Monte Carlo simulations to account for the biases introduced by the discontinuous sampling and the low-count regime. We confirm that variability is an ubiquitous property of AGNs, with no clear dependence on the density of the environment. The variability properties of high-z AGNs, over different temporal timescales, are most consistent with a Power Spectral Density (PSD) de…
Over the last decade, X-ray observations of Sgr A* have revealed a black hole in a deep sleep, punctuated roughly once per day by brief flares. The extreme X-ray faintness of this supermassive black hole has been a long-standing puzzle in black hole accretion. To study the accretion processes in the Galactic Center, Chandra (in concert with numerous ground- and space-based observatories) undertook a 3 Ms campaign on Sgr A* in 2012. With its excellent observing cadence, sensitivity, and spectral resolution, this Chandra X-ray Visionary Project (XVP) provides an unprecedented opportunity to stud…
Extragalactic X-ray surveys are exceptionally powerful tools for studying the evolution of supermassive black holes and their host galaxies, by detecting large numbers of active galactic nuclei (AGN) and star-forming galaxies over a wide range of redshifts and cosmic environments. With its sensitivity and superb angular resolution, Chandra has been at the forefront of recent extragalactic surveys. This article provides a brief overview of Chandra surveys, and highlights a few recent results on the composition of the cosmic X-ray background, insights on X-ray source populations, and links betwe…
We review results from cosmic X-ray surveys of active galactic nuclei (AGNs) over the past ~ 15 yr that have dramatically improved our understanding of growing supermassive black holes in the distant universe. First, we discuss the utility of such surveys for AGN investigations and the capabilities of the missions making these surveys, emphasizing Chandra, XMM-Newton, and NuSTAR. Second, we briefly describe the main cosmic X-ray surveys, the essential roles of complementary multiwavelength data, and how AGNs are selected from these surveys. We then review key results from these surveys on the …
We present a study of relations between the masses of the central supermassive black holes (SMBHs) and the atmospheric gas temperatures and luminosities measured within a range of radii between $R_{\rm e}$ and 5$R_{\rm e}$, for a sample of 47 early-type galaxies observed by the {\it Chandra X-ray Observatory}. We report the discovery of a tight correlation between the atmospheric temperatures of the brightest cluster/group galaxies (BCGs) and their central SMBH masses. Furthermore, our hydrostatic analysis reveals an approximately linear correlation between the total masses of BCGs ($M_{\rm to…
An extraordinary recent development in astrophysics was the discovery of the fossil relationship between central black hole mass and the stellar mass of galactic bulges. The physical process underpinning this relationship has become known as feedback. The Chandra X-ray Observatory was instrumental in realizing the physical basis for feedback, by demonstrating a tight coupling between the energy released by supermassive black holes and the gaseous structures surrounding them. This white paper discusses how a great leap forward in X-ray collecting area and spectral resolution will allow a qualit…
We investigate the evolution of supermassive binary black holes (BBHs) in galaxies with realistic property distributions and the gravitational-wave (GW) radiation from the cosmic population of these BBHs. We incorporate a comprehensive treatment of the dynamical interactions of the BBHs with their environments by including the effects of galaxy triaxial shapes and inner stellar distributions, and generate a large number of BBH evolution tracks. By combining these BBH evolution tracks, galaxy mass functions, galaxy merger rates, and supermassive black hole-host galaxy relations into our model, …
From a Chandra sample of active galactic nuclei (AGNs) in nearby galaxies, we find that for low-luminosity AGNs (LLAGNs), either the intrinsic absorption column density, or the fraction of absorbed AGNs, positively scales with the Eddington ratio for $L_{\rm bol}/L_{\rm Edd} \lesssim 10^{-2}$. Such a behavior, along with the softness of the X-ray spectrum at low luminosities, is in good agreement with the picture that they are powered by hot accretion flows surrounding supermassive black holes. Numerical simulations find that outflows are inevitable with hot accretion flows, and the outflow ra…
A supermassive black hole (SMBH) of $\sim 3\times 10^6 \, \rm M_\odot$ was recently detected via dynamical measurements at the center of the dwarf galaxy Leo I. Standing $\sim 2$ orders of magnitude above standard scaling relations, this SMBH is hosted by a galaxy devoid of gas and with no significant star formation in the last $\sim 1$ Gyr. This detection can profoundly impact the formation models for black holes and their hosts. We propose that winds from a population of $\sim 100$ evolved stars within the Bondi radius of the SMBH produce a sizable accretion rate, with Eddington ratios betwe…
Observational confirmation of hot accretion model predictions has been hindered by the challenge to resolve spatially the Bondi radii of black holes with X-ray telescopes. Here, we use the Megasecond Chandra X-ray Visionary Project (XVP) observation of the NGC~3115 supermassive black hole to place the first direct observational constraints on the spatially and spectroscopically resolved structures of the X-ray emitting gas inside the Bondi radius of a black hole. We measured temperature and density profiles of the hot gas from a fraction out to tens of the Bondi radius (R_B = 2.4-4.8 arcsec = …
The magnetar SGR J1745-2900 discovered at parsecs distance from the Milky Way central black hole, Sagittarius A*, represents the closest pulsar to a supermassive black hole ever detected. Furthermore, its intriguing radio emission has been used to study the environment of the black hole, as well as to derive a precise position and proper motion for this object. The discovery of SGR J1745-2900 has opened interesting debates about the number, age and nature of pulsars expected in the Galactic center region. In this work, we present extensive X-ray monitoring of the outburst of SGR J1745-2900 usi…
The vast majority of supermassive black holes (SMBHs) in the local universe exhibit levels of activity much lower than those expected from gas supplying rates onto the galactic nuclei, and only a small fraction of silent SMBHs can turn into active galactic nuclei. Revisiting observational data of very nearby SMBHs whose gravitational spheres of influence are spatially reached by the Chandra X-ray satellite, we find that the level of BH activity drastically increases from the quiescent phase when the inflow rate outside of the BH influence radius is higher than 0.1% of the Eddington accretion r…
As matter accretes onto the central supermassive black holes in active galactic nuclei (AGN), X-rays are emitted. We present a population synthesis model that accounts for the summed X-ray emission from growing black holes; modulo the efficiency of converting mass to X-rays, this is effectively a record of the accreted mass. We need this population synthesis model to reproduce observed constraints from X-ray surveys: the X-ray number counts, the observed fraction of Compton-thick AGN [$\log$ (N$_{\rm H}$/cm$^{\rm -2}$) $>$ 24] and the spectrum of the cosmic X-ray background (CXB), after accoun…
Dynamical mass measurements to date have allowed determinations of the mass M and the distance D of a number of nearby supermassive black holes. In the case of Sgr A*, these measurements are limited by a strong correlation between the mass and distance scaling roughly as M ~ D^2. Future very-long baseline interferometric (VLBI) observations will image a bright and narrow ring surrounding the shadow of a supermassive black hole, if its accretion flow is optically thin. In this paper, we explore the prospects of reducing the correlation between mass and distance with the combination of dynamical…
Sagittarius A* is a compact radio source at the Galactic center, powered by accretion of fully ionized plasmas into a supermassive black hole. However, the radio emission cannot be produced through the thermal synchrotron process by a gravitationally bounded flow. General relativistic magneto-hydrodynamical(GRMHD) simulations of black hole accretion show that there are strong unbounded outflows along the accretion. With the flow structure around the black hole given by GRMHD simulations, we investigate whether thermal synchrotron emission from these outflows may account for the observed radio …
An unusual object, G2, had its pericenter passage around Sgr A*, the $4\times10^6$ M$_\odot$ supermassive black hole in the Galactic Centre, in Summer 2014. Several research teams have reported evidence that following G2's pericenter encounter the rate of Sgr A*'s bright X-ray flares increased significantly. Our analysis carefully treats varying flux contamination from a nearby magnetic neutron star and is free from complications induced by using data from multiple X-ray observatories with different spatial resolutions. We test the scenario of an increased bright X-ray flaring rate using a mas…
Recent observations of nearby Compton thick (CT) active galactic nuclei (AGNs) with Chandra have resolved hard (>3 keV) X-ray emission extending out from the central supermassive black hole to kiloparsec scales, challenging the long-held belief that the characteristic hard X-ray continuum and fluorescent Fe K lines originate in the inner ~parsec due to the excitation of obscuring material. In this paper we present the results of the most recent Chandra ACIS-S observations of NGC 7212, a CT AGN in a compact group of interacting galaxies, with a total effective exposure of ~150 ks. We find ~20 p…
Galaxy-scale bars are expected to provide an effective means for driving material towards the central region in spiral galaxies, and possibly feeding supermassive black holes (BHs). Here we present a statistically-complete study of the effect of bars on average BH accretion. From a well-selected sample of 50,794 spiral galaxies (with M* ~ 0.2-30 x 10^10 Msun) extracted from the Sloan Digital Sky Survey Galaxy Zoo 2 project, we separate those sources considered to contain galaxy-scale bars from those that do not. Using archival data taken by the Chandra X-ray Observatory, we identify X-ray lumi…
Pulsar timing arrays (PTAs) are placing increasingly stringent constraints on the strain amplitude of continuous gravitational waves emitted by supermassive black hole binaries on subparsec scales. In this paper, we incorporate independent information about the dynamical masses $M_{bh}$ of supermassive black holes in specific galaxies at known distances and use this additional information to further constrain whether or not those galaxies could host a detectable supermassive black hole binary. We estimate the strain amplitudes from individual binaries as a function of binary mass ratio for two…
A supermassive black hole under the radar: Repeating X-ray variability in a Seyfert galaxy
Università degli Studi di Roma “Tor Vergata”（罗马托尔维加塔大学）；INAF – Osservatorio Astronomico di Roma（罗马天文台（意大利国家天体物理研究所））；Università degli Studi di Roma “La Sapienza”（罗马第一大学）；Centro de Astrobiología (CAB), CSIC-INTA（西班牙国家研究委员会-国家航空航天技术研究所天体生物学中心）；INFN – Roma Tor Vergata（罗马托尔维加塔国立核物理研究所）
We present results from three nearly simultaneous NuSTAR and Chandra monitoring observations between 2012 Sep 2 and 2012 Nov 16 of local star-forming galaxy NGC 253. The 3-40 keV NuSTAR intensity of the inner 20 arcsec (~400 pc) nuclear region varied by a factor of ~2 across the three monitoring observations. The Chandra data reveal that the nuclear region contains three bright X-ray sources, including a luminous (L2-10 keV ~ few x 10^39 erg/s) point source ~1 arcsec from the dynamical center of the galaxy (within the 3sigma positional uncertainty of the dynamical center); this source drives t…
We report on Chandra observations of the bright ultra-luminous X-ray (ULX) source in NGC3921. Previous XMM observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2x10^40 erg/s. Our Chandra observation finds the source at a lower luminosity of ~8x10^39 erg/s, furthermore, we provide a Chandra position of the ULX accurate to 0.7" at 90% confidence. The X-ray variability makes it unlikely that the high luminosity is caused by several separate X-ray sources. In 3 epochs of archival Hubble Space Telescope (HST) observations we find a candidate counte…
We study the collapse of rapidly rotating supermassive stars that may have formed in the early Universe. By self-consistently simulating the dynamics from the onset of collapse using three-dimensional general-relativistic hydrodynamics with fully dynamical spacetime evolution, we show that seed perturbations in the progenitor can lead to the formation of a system of two high-spin supermassive black holes, which inspiral and merge under the emission of powerful gravitational radiation that could be observed at redshifts z>10 with the DECIGO or Big Bang Observer gravitational-wave observatories,…
Over the past 13 years, the Chandra X-ray Observatory's ability to provide high resolution X-ray images and spectra have established it as one of the most versatile and powerful tools for astrophysical research in the 21st century. Chandra explores the hot, x-ray-emitting regions of the universe, observing sources with fluxes spanning more than 10 orders of magnitude, from the X-ray brightest, Sco X-1, to the faintest sources in the Chandra Deep Field South survey. Thanks to its continuing operational life, the Chandra mission now also provides a long observing baseline which, in and of itself…
In active galactic nuclei (AGN), fluorescent Fe K$α$ (iron) line emission is generally interpreted as originating from obscuring material around a supermassive black hole (SMBH) on the scale of a few parsecs (pc). However, recent Chandra studies indicate the existence of iron line emission extending to kpc scales in the host galaxy. The connection between iron line emission and large-scale material can be spatially resolved directly only in nearby galaxies, but could be inferred in more distant AGNs by a connection between line emission and star-forming gas and dust that is more extended than …
We report the detection of a weak X-ray point source coincident with the nucleus of the bulgeless disk galaxy NGC 3621, recently discovered by Spitzer to display high ionization mid-infrared lines typically associated with AGN. These Chandra observations provide confirmation for the presence of an AGN in this galaxy, adding to the growing evidence that black holes do form and grow in isolated bulgeless disk galaxies. Although the low signal-to-noise ratio of the X-ray spectrum prevents us from carrying out a detailed spectral analysis of the nuclear source, the X-ray results, combined with the…
We present new mass measurements for the supermassive black holes (SMBHs) in the centres of three early-type galaxies. The gas pressure in the surrounding, hot interstellar medium (ISM) is measured through spatially resolved spectroscopy with the Chandra X-ray observatory, allowing the SMBH mass (Mbh) to be inferred directly under the hydrostatic approximation. This technique does not require calibration against other SMBH measurement methods and its accuracy depends only on the ISM being close to hydrostatic, which is supported by the smooth X-ray isophotes of the galaxies. Combined with resu…
Within 40 years of the detection of the first extrasolar X-ray source in 1962,NASA's Chandra X-ray Observatory has achieved an increase in sensitivity of 10 orders of magnitude, comparable to the gain in going from naked-eye observations to the most powerful optical telescopes over the past 400 years. Chandra is unique in its capabilities for producing sub-arcsecond X-ray images with 100-200 eV energy resolution for energies in the range 0.08<E<10 keV, locating X-ray sources to high precision, detecting extremely faint sources, and obtaining high resolution spectra of selected cosmic phenomena…
Recently we discovered an unprecedented supermassive black hole binary (SMBHB) candidate in the nearby Seyfert galaxy SDSS J1430+2303, which is predicted to merge within three years. X-ray spectroscopy may bring unique kinematic evidence for the last inspiraling stage, when the binary is too close to allow each of them to hold an individual broad line region. We try to confirm the unique SMBHB merger event and understand the associated high-energy processes from a comprehensive X-ray view. We observed SDSS J1430+2303 with XMM-Newton, NuSTAR, Chandra, and Swift spanning the first ~200 days sinc…
The mechanism by which the supermassive black holes that power bright quasars at high redshift form remains unknown. One possibility is that ... the monolithic collapse of a massive protogalactic disc ... leads to the formation of a quasi-star: a growing black hole, initially of typical stellar-mass, embedded in a hydrostatic giant-like envelope. Quasi-stars are the main object of study in this dissertation. ... In Chapter 1, I introduce the problem posed by the supermassive black holes that power high-redshift quasars. ... In Chapter 2, I outline the Cambridge STARS code and the modifications…
The supermassive black hole at the Galactic center, Sagittarius A*, has experienced periods of higher activity in the past. The reflection of these past outbursts is observed in the molecular material surrounding the black hole but reconstructing its precise lightcurve is difficult since the distribution of the clouds along the line of sight is poorly constrained. Using Chandra high-resolution data collected from 1999 to 2011 we studied both the 6.4 keV and the 4-8 keV emission of the region located between Sgr A* and the Radio Arc, characterizing its variations down to 15" angular scale and 1…
We present the rest-frame optical morphologies of active galactic nucleus (AGN) host galaxies at 1.5<z<3, using near-infrared imaging from the Hubble Space Telescope Wide Field Camera 3, the first such study of AGN host galaxies at these redshifts. The AGN are X-ray selected from the Chandra Deep Field South and have typical luminosities of 1E42 < L_X < 1E44 erg/s. Accreting black holes in this luminosity and redshift range account for a substantial fraction of the total space density and black hole mass growth over cosmic time; they thus represent an important mode of black hole growth in the…
M87, the active galaxy at the center of the Virgo cluster, is ideal for studying the interaction of a supermassive black hole (SMBH) with a hot, gas-rich environment. A deep Chandra observation of M87 exhibits an approximately circular shock front (13 kpc radius, in projection) driven by the expansion of the central cavity (filled by the SMBH with relativistic radio-emitting plasma) with projected radius $\sim$1.9 kpc. We combine constraints from X-ray and radio observations of M87 with a shock model to derive the properties of the outburst that created the 13 kpc shock. Principal constraints …
We present a detailed spectral analysis of new XMM-Newton data of the source CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z = 0.359. Previous works suggested that CID-42 is a candidate recoiling supermassive black holes showing also an inverted P-Cygni profile in the X- ray spectra at ~6 keV (rest) with an iron emission line plus a redshifted absorption line (detected at 3sigma in previous XMM-Newton and Chandra observations). Detailed analysis of the absorption line suggested the presence of ionized material inflowing into the black hole at high velocity. In t…
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…
The center of our Galaxy hosts a supermassive black hole, Sagittarius (Sgr) A*. Young, massive stars within 0.5 pc of SgrA* are evidence of an episode of intense star formation near the black hole a few Myr ago, which might have left behind a young neutron star traveling deep into SgrA*'s gravitational potential. On 2013 April 25, a short X-ray burst was observed from the direction of the Galactic center. Thanks to a series of observations with the Chandra and the Swift satellites, we pinpoint the associated magnetar at an angular distance of 2.4+/-0.3 arcsec from SgrA*, and refine the source …
In this paper, we explore the mechanisms that regulate the formation and evolution of stellar black hole binaries (BHBs) around supermassive black holes (SMBHs). We show that dynamical interactions can efficiently drive "in-situ" BHB formation if the SMBH is surrounded by a massive nuclear cluster (NC), while orbitally segregated star clusters can replenish the BHB reservoir in SMBH-dominated nuclei. We discuss how the combined action of stellar hardening and mass segregation sculpts the BHB orbital properties. We use direct N-body simulations including post-Newtonian corrections up to 2.5 ord…
We estimate the gravitational radiation signature of the electron/positron annihilation-driven neutrino burst accompanying the asymmetric collapse of an initially hydrostatic, radiation-dominated supermassive object suffering the Feynman-Chandrasekhar instability. An object with a mass $5\times10^4\,M_\odot<M<5\times10^5\,M_\odot$, with primordial metallicity, is an optimal case with respect to the fraction of its rest mass emitted in neutrinos as it collapses to a black hole: lower initial mass objects will be subject to scattering-induced neutrino trapping and consequently lower efficiency i…
We report a sensitive X-ray search for the proposed intermediate mass black hole (IMBH) in the massive Galactic cluster, Omega Centauri (NGC 5139). Combining Chandra X-ray Observatory data from Cycles 1 and 13, we obtain a deep (~291 ks) exposure of the central regions of the cluster. We find no evidence for an X-ray point source near any of the cluster's proposed dynamical centers, and place an upper limit on the X-ray flux from a central source of f_X(0.5-7.0 keV) <= 5.0x10^-16 erg cm^-2 s^-1, after correcting for absorption. This corresponds to an unabsorbed X-ray luminosity of L_X(0.5-7.0 …
We confirm our earlier tentative detection of M31* in X-rays and measure its light-curve and spectrum. Observations in 2004-2005 find M31* rather quiescent in the X-ray and radio. However, X-ray observations in 2006-2007 and radio observations in 2002 show M31* to be highly variable at times. A separate variable X-ray source is found near P1, the brighter of the two optical nuclei. The apparent angular Bondi radius of M31* is the largest of any black hole, and large enough to be well resolved with Chandra. The diffuse emission within this Bondi radius is found to have an X-ray temperature ~0.3…
We put active galactic nuclei (AGNs) with low-mass black holes on the fundamental plane of black hole accretion---the plane that relates X-ray emission, radio emission, and mass of an accreting black hole---to test whether or not the relation is universal for both stellar-mass and supermassive black holes. We use new Chandra X-ray and Very Large Array radio observations of a sample of black holes with masses less than $10^{6.3}\ M_{\scriptscriptstyle \odot}$, which have the best leverage for determining whether supermassive black holes and stellar-mass black holes belong on the same plane. Our…
The effect of pressure confinement on the maximum mass of rapidly accreting supermassive stars
Niels Bohr International Academy, The Niels Bohr Institute（尼尔斯·玻尔国际学院，尼尔斯·玻尔研究所）；Center of Gravity, Niels Bohr Institute（引力中心，尼尔斯·玻尔研究所）；Institute of Science and Technology Austria (ISTA)（奥地利科学与技术研究所）
