Description
Chairman: Jiří Horák
We perform global 2D axisymmetric general relativistic radiation magnetohydrodynamic simulations of super-critical disk accretion onto a neutron star with a modest dipolar magnetic field strength of 20 GigaGauss as a model of a ULX. We study the effect of the boundary condition on the structure of the accretion column, outflow, and radiative output. In addition to fully absorbing and...
In our 3D numerical simulations of accretion disk around a supermassive black hole with the GRMHD code Athena++, we follow the time evolution of magnetic field. In the case of SANE configuration, with multiple loops of oppositely directed initial poloidal magnetic field in the torus around a black hole, we follow the forming of flux ropes atop the disk, and their release into corona.
Long term observations of black-hole X-ray binaries show that these systems exhibit extreme, aperiodic variability on time scales of few milliseconds to seconds. The observed light-curves display various characteristic features like log-normal distribution and linear rms-flux relation, which indicates that the underlying variability process is stochastic in nature and is thought to be...
We perform resistive MHD simulations of accretion disk with alpha-viscosity, accreting onto a rotating star endowed with a magnetic dipole. We find backflow in the presence of strong magnetic field and large resistivity, and probe for the dependence on Prandtl number. We find that in the magnetic case the distance from the star at which backflow begins, the stagnation radius, is different than...