Related papers: Magnetized accretion-ejection structures V. Effect…
We examine, parametrically, the interaction between the magnetosphere of a rotating, young stellar object (YSO) and a circumstellar accretion disk using 2.5-D (cylindrically symmetric) numerical magnetoydrodynamic simulations. The…
Three energy mechanisms invoking large-scale magnetic fields are incorporated in a model to interpret jet production in black hole (BH) systems, i.e., the Blandford-Znajek (BZ), the magnetic coupling (MC) and Blandford-Payne (BP) processes.…
The formation of astrophysical objects of different nature and size, from black holes to gaseous giant planets, involves a disk-jet system, where the disk drives the mass accretion onto a central compact object and the jet is a fast…
We study, by means of numerical simulations and analysis, the details of the accretion process from a disc onto a binary system. We show that energy is dissipated at the edge of a circumbinary disc and this is associated with the tidal…
In the current paradigm of star formation magnetic fields play a very central role. Indeed, they probably help or even channel the initial gravitational collapse of the parent molecular cloud. But their most spectacular effect is certainly…
Relativistic jets and disc-winds are typically observed in BH-XRBs and AGNs. However, many physical details of jet launching and the driving of disc winds from the underlying accretion disc are still not fully understood. In this study, we…
We present a detailed calculation of the mechanism by which the Accretion-Ejection Instability can extract accretion energy and angular momentum from a magnetized disk, and redirect them to its corona. In a disk threaded by a poloidal…
Using Chandra X-ray observations of 9 nearby, X-ray luminous ellipticals with good optical velocity dispersion measurements, we show that a tight correlation exists between the Bondi accretion rates calculated from the X-ray data and…
Global 3-D magnetohydrodynamical simulations have been conducted to study magnetospheric accretion around stars with various spin rates. For slow rotators, characterized by a fastness parameter $\omega_s\lesssim 0.78$, the disk's inner edge…
In this paper we use the imaging results of M87* from the EHT to calculate the rotational velocity of the inner edge of the accretion disk and find a value of $\sim$0.14c. We then calculate the dimensionless spin parameter, $a$, of the…
Recently, Allen et al. measured a tight correlation between the Bondi accretion rates and jet powers of the nuclei of nearby X-ray luminous elliptical galaxies. We employ two models of jet powering to understand the above correlation and…
We discuss the problem of the formation of a large-scale magnetic field in the accretion disks around black holes, taking into account the nonuniform vertical structure of the disk. The high electrical conductivity of the outer layers of…
Accretion discs are composed of ionized gas in motion around a central object. Sometimes, the disc is the source of powerful bipolar jets along its rotation axis. Theoretical models invoke the existence of a bipolar magnetic field crossing…
The formation of jets in black hole accretion systems is a long-standing problem. It has been proposed that a jet can be formed by extracting the rotation energy of the black hole ("BZ-jet") or the accretion flow ("disk-jet"). While both…
I review our current theoretical understanding of the different possible rotating modes of accretion onto a black hole. I discuss both thick adiabatic flows and radiatively efficient thin disc solutions. I present a new self-consistent…
Jet powers in many radio galaxies with extended radio structures appear to exceed their associated accretion luminosities. In systems with very low accretion rates, this is likely due to the very low accretion luminosities resulting from…
Winds are commonly observed in luminous active galactic nuclei (AGNs). A plausible model of those winds is magnetohydrodynamic (MHD) disc winds. In the case of disc winds from a thin accretion disc, isothermal or adiabatic assumption is…
We investigate the evolution of a disk wind into a collimated jet under the influence of magnetic diffusivity, assuming that the turbulent pattern in the disk will also enter the disk corona and the jet. Using the ZEUS-3D code in the…
The magneto-centrifugal model for jet formation is studied by time-dependent simulations reaching steady state in a cold gas with negligible fluid pressure, in an axisymmetric geometry, using a modification of the Zeus3D code adapted to…
This paper continues the analysis of a set of general relativistic 3D MHD simulations of accreting tori in the Kerr metric with different black hole spins. We focus on bound matter inside the initial pressure maximum, where the…