Related papers: Toward precise constraints on growth of massive bl…
In this work we study the co-evolution of central black holes (BHs) and host galaxies by utilizing an advanced iteration of the DELPHI semi-analytical model of galaxy formation and evolution. Based on dark matter halo merger trees spanning…
We derive the mass function of supermassive black holes (SMBHs) over the redshift range 0<z<2, using the latest deep luminosity and mass functions of field galaxies. Applying this mass function, combined with the bolometric luminosity…
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…
A multitude of JWST studies reveal a surprising over-abundance of over-massive accreting super-massive black holes (SMBHs) -- leading to a deepening tension between theory and observation in the first billion years of cosmic time. Across…
In this work we revisit the growth of small primordial black holes (PBHs) immersed in a quintessential field and/or radiation to the supermassive black hole (SMBHs) scale. We show the difficulties of scenarios in which such huge growth is…
Based on the physical model of a supermassive black hole (SMBH) growth via gas accretion in a circumnuclear disk (CND) proposed by Kawakatu & Wada (2008), we describe the formation of high-$z$ ($z > 6$) quasars (QSOs) whose BH masses are…
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…
We suggest a common physical origin connecting the fast, highly ionized winds (UFOs) seen in nearby AGN, and the slower and less ionized winds of BAL QSOs. The primary difference is the mass loss rate in the wind, which is ultimately…
We combine cosmological hydrodynamic simulations with analytic models to evaluate the role of galaxy-scale gravitational torques on the evolution of massive black holes at the centers of star-forming galaxies. We confirm and extend our…
We investigate a large number of cosmological evolution models for QSOs and Active Galactic Nuclei (AGN). We introduce a spectrum-luminosity correlation as a new input parameter and adopt the estimated mass function (MF) of massive black…
The tight correlation between the masses of central black holes and their host spheroids in nearby galaxies and active galactic nuclei suggests that black hole growth is closely related to their spheroid formation. Based on our previous…
Virial black-hole mass estimates are presented for 12698 quasars in the redshift interval 0.1<z<2.1, based on modelling of spectra from the Sloan Digital Sky Survey (SDSS) first data release. The black-hole masses of the SDSS quasars are…
Theoretical models predict that a population of Intermediate Mass Black Holes (IMBHs) of mass $M_\bullet \approx 10^{4-5} \, \mathrm{M_{\odot}}$ might form at high ($z > 10$) redshift by different processes. Such objects would represent the…
It is well established that cosmic supermassive black hole (SMBH) growth peaks at $z\approx1.5-2$, followed by a strong decline of $\approx1-1.5\,\rm dex$ toward the present day, with the comoving number density of higher-luminosity active…
Understanding the relationship between the formation and evolution of galaxies and their central super massive black holes (SMBH) is one of the main topics in extragalactic astrophysics. Links and feedback may reciprocally affect both black…
I show that there is a physical limit to the mass of a black hole, above which it cannot grow through luminous accretion of gas, and so cannot appear as a quasar or active galactic nucleus. The limit is Mmax \simeq 5x10^{10}M_sun for…
If supermassive black holes (SMBHs) are the energy sources that power quasars and active galactic nuclei, then QSO SDSS 1148+5251, the quasar with the highest redshift (z_QSO=6.43), hosts a supermassive black hole formed within 0.9 Gyr…
The Sloan Digital Sky survey detected luminous quasars at very high redshift, z>6. Follow-up observations indicated that at least some of these quasars are powered by supermassive black holes (SMBHs) with masses in excess of billion solar…
The cosmological evolution of Active Galactic Nuclei (AGN) is important for understanding the mechanism of accretion onto supermassive black holes, and the related evolution of the host galaxy. In this work, we include objects with very low…
Presently, it is unclear whether the Eddington ratio and radiative efficiency depend upon a supermassive black hole's (SMBH's) redshift z and mass MBH. We attempt to resolve this issue using published data for 132,000 SMBHs with MBH >1E+7…