相关论文: Magnetic flux stabilizing thin accretion disks
We report on simulations in general relativity of magnetized disks onto black hole binaries. We vary the binary mass ratio from 1:1 to 1:10 and evolve the systems when they orbit near the binary-disk decoupling radius. We compare (surface)…
Magnetic fields play a central role in black hole astrophysics, powering relativistic jets and other energetic phenomena. While near-horizon magnetic field is usually assumed to originate from the accretion flow, additional large-scale…
The magnetorotational instability originates from the elastic coupling of fluid elements in orbit around a gravitational well. Since inertial accelerations play a fundamental dynamical role in the process, one may expect substantial…
We consider the combined role of the thermal ionization, magneto-rotational and gravitational instabilities in thin accretion disks around supermassive black holes. We find that in the portions of the disk unstable to the ionization…
Many accreting systems are modeled as geometrically thin disks. Simulations of accretion disks cannot be extended to this regime, although local models can address the behavior of narrow annuli. A global model needs to account for the…
In some Seyfert Galaxies, the hard X-rays that produce fluorescent emission lines are thought to be generated in a hot corona that is compact and located at only a few gravitational radii above the supermassive black hole. We consider the…
We present the results of four three-dimensional radiation magnetohydrodynamic simulations of accretion disks around a $10^8$ solar mass black hole, which produce the far ultraviolet spectrum peak and demonstrate a robust physical mechanism…
We studied magnetically arrested disks (MAD) around rotating black holes (BH), under the influence of radiative cooling. We introduce a critical value of the mass accretion rate $\dot M_{\rm crit}$ for which the cooling by the synchrotron…
We use a global magnetohydrodynamic simulation of a geometrically thin accretion disk to investigate the locality and detailed structure of turbulence driven by the magnetorotational instability (MRI). The model disk has an aspect ratio $H…
We studied the magnetic field structures and dynamics of magnetized multiphase gas on parsec scales around supermassive black holes by using global 3D magnetohydrodynamics (MHD) simulations. We considered the effect of radiative cooling and…
Recent observations of SgrA* by the GRAVITY instrument have astrometrically tracked infrared flares (IR) at distances of $\sim 10$ gravitational radii ($r_g$). In this paper, we study a model for the flares based on 3D general relativistic…
The flow of a matter, accreting onto a magnetized neutron star, is accompanied by an electric current. The closing of the electric current occurs in the crust of a neutron stars in the polar region across the magnetic field. But the…
Aims: We determine the steady-state of an axisymmetric thin accretion disc with an internal dynamo around a magnetised star. Methods: Starting from the vertically integrated equations of magnetohydrodynamics we derive a single ordinary…
Strong magnetization in accretion discs could resolve a number of outstanding issues related to stability and state transitions in low-mass X-ray binaries. However, it is unclear how real discs become strongly magnetized and, even if they…
In accretion disks with large-scale ordered magnetic fields, the magnetorotational instability (MRI) is marginally suppressed, so other processes may drive angular momentum transport leading to accretion. Accretion could then be driven by…
We present an instability, occurring in the inner region of magnetized accretion disks, which seems to be a good candidate to explain the low-frequency QPO observed in many X-ray binaries. We then briefly show how, in the remarkable case of…
Using magnetohydrodynamic (MHD) adaptive mesh refinement simulations, we study the formation and early evolution of disk galaxies with a magnetized interstellar medium. For a $10^{10}$ \msun halo with initial NFW dark matter and gas…
We investigate the thermal stability of optically thin, two-temperature, radiative cooling-dominated accretion disks. Our linear analysis shows that the disk is thermally unstable without magnetic fields, which agrees with previous…
A common assumption used in the study of accretion disks is that the magnetic energy density and the kinetic energy density should be in equipartition. This assumption relies on the faster growth rate of the magnetic field strength against…
We estimated the magnetic field strength at the horizon radius of black holes, that is derived by the magnetic coupling process and depended on the black hole mass $M_{BH}$ and the accretion rate $\dot{M}$. Our estimation is based on the…