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Understanding the physics and geometry of accretion and ejection around super massive black holes (SMBHs) is important to understand the evolution of active galactic nuclei (AGN) and therefore of the large scale structures of the Universe. We aim at providing a simple, coherent, and global view of the sub-parsec accretion and ejection flow in AGN with varying Eddington ratio, $dot{m}$, and black hole mass, $M_{BH}$. We made use of theoretical insights, results of numerical simulations, as well as UV and X-ray observations to review the inner regions of AGN by including different accretion and ejection modes, with special emphasis on the role of radiation in driving powerful accretion disk winds from the inner regions around the central SMBH. We propose five $dot{m}$ regimes where the physics of the inner accretion and ejection flow around SMBHs is expected to change, and that correspond observationally to quiescent and inactive galaxies; low luminosity AGN (LLAGN); Seyferts and mini-broad absorption line quasars (mini-BAL QSOs); narrow line Seyfert 1 galaxies (NLS1s) and broad absorption line quasars (BAL QSOs); and super-Eddington sources. We include in this scenario radiation-driven disk winds, which are strong in the high $dot{m}$, large $M_{BH}$ regime, and possibly present but likely weak in the moderate $dot{m}$, small $M_{BH}$ regime. A great diversity of the accretion/ejection flows in AGN can be explained to a good degree by varying just two fundamental properties: the Eddington ratio $dot{m}$ and the black hole mass $M_{BH}$, and by the inclusion of accretion disk winds that can naturally be launched by the radiation emitted from luminous accretion disks.
To explain the observed population of supermassive black holes at z~7, very massive seed black holes or, alternatively, super-Eddington scenarios are needed to reach final masses of the order of 10^9 solar masses. A popular explanation for massive se
We study the small scale magnetic reconnection above the radiative inefficient accretion flow around massive black hole via 2D magnetohydrodynamics (MHD) numerical simulation, in order to model the blob formation and ejection from the accretion flow
We use global three dimensional radiation magneto-hydrodynamical simulations to study accretion disks onto a $5times 10^8M_{odot}$ black hole with accretion rates varying from $sim 250L_{Edd}/c^2$ to $1500 L_{Edd}/c^2$. We form the disks with torus c
The rapid assembly of the massive black holes that power the luminous quasars observed at $z sim 6-7$ remains a puzzle. Various direct collapse models have been proposed to head-start black hole growth from initial seeds with masses $sim 10^5,rm M_od
Hyperaccretion occurs when the gas inflow rate onto a black hole (BH) is so high that the radiative feedback cannot reverse the accretion flow. This extreme process is a promising mechanism for the rapid growth of seed BHs in the early universe, whic