相关论文: A dormant, overmassive black hole in the early Uni…
The formation of the first massive objects in the infant Universe remains impossible to observe directly and yet it sets the stage for the subsequent evolution of galaxies. While some black holes with masses > billion solar masses? have…
Recent James Webb Space Telescope (JWST) observations have revealed a surprisingly abundant population of faint, dusty active galactic nuclei (AGNs) at z~4-7. Together with the presence of supermassive black holes (SMBHs) at z>6, this…
The recent discovery of a large number of massive black holes within the first two billion years after the Big Bang, as well as their peculiar properties, have been largely unexpected based on the extrapolation of the properties of luminous…
Supermassive black holes with up to a $\rm 10^{9}~M_{\odot}$ dwell in the centers of present-day galaxies, and their presence has been confirmed at z $\geq$ 6. Their formation at such early epochs is still an enigma. Different pathways have…
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…
One possible scenario for the formation of massive black holes (BHs) in the early Universe is from the direct collapse of primordial gas in atomic-cooling dark matter haloes in which the gas is unable to cool efficiently via molecular…
We consider a scenario where supermassive black holes form through direct accumulation of gas at the centre of proto-galaxies. In the first stage, the accumulated gas forms a super-massive star whose core collapses when the nuclear fuel is…
Supermassive black holes (SMBHs) and their host galaxies are generally thought to coevolve, so that the SMBH achieves up to about 0.2 to 0.5% of the host galaxy mass in the present day. The radiation emitted from the growing SMBH is…
We investigate the steady spherically symmetric accretion in the combined potential of a central black hole and a dark matter halo. For the halo, we consider a Hernquist and an NFW potential and calculate the critical points of the flow. We…
We consider the distribution of local supermassive black hole Eddington ratios and accretion rates, accounting for the dependence of radiative efficiency and bolometric corrections on the accretion rate. We find that black hole mass growth,…
Super-Eddington accretion onto massive black hole seeds may be commonplace in the early Universe, where the conditions exist for rapid accretion. Direct collapse black holes are often invoked as a possible solution to the observation of…
It is argued that supermassive black holes in the nuclei of galaxies most likely have grown coevally with their host dark matter halos. A calculation based on Press-Schechter within this framework shows that the mean rate of accretion of…
While large numbers of supermassive black holes have been detected at z>6, their origin is still essentially unclear. Numerical simulations have shown that the conditions for the classical direct collapse scenario are very restrictive and…
Observations by the James Webb Space Telescope of the Universe at $z\gtrsim 4$ have shown that massive black holes (MBHs) appear extremely overmassive compared to the local correlation for active galactic nuclei. In some cases, these…
The formation, accretion and growth of supermassive black holes in the early universe are investigated. The accretion rate ${\dot M}$ is calculated using the Bondi accretion rate onto black holes. Starting with initial seed black holes with…
We constrain the total accreted mass density in supermassive black holes at z>6, inferred via the upper limit derived from the integrated X-ray emission from a sample of photometrically selected galaxy candidates. Studying galaxies obtained…
The origin of the supermassive black holes that power the most distant quasars observed is largely unknown. One hypothesis is that they grew rapidly from intermediate-mass seeds (~100 M_sun) left by the first stars. However, some previous…
Early JWST observations are providing growing evidence for a ubiquitous population of accreting supermassive black holes (BHs) at high redshift, many of which appear overmassive compared to the empirically-derived local scaling relation…
Mass accretion by black holes (BHs) is typically capped at the Eddington rate, when radiation's push balances gravity's pull. However, even exponential growth at the Eddington-limited e-folding time t_E ~ few x 0.01 billion years, is too…
We report on a calculation of the growth of the mass of supermassive black holes at galactic centers from dark matter and Eddington - limited baryonic accretion. Assuming that dark matter halos are made of fermions and harbor compact…