If accretion disc contains weak frozen-in entangled magnetic fields, their dynamical effect may be important inside the last stable orbit because of the decompression near the sonic point. Here, I consider the radial and vertical structure of a nearl
y free-falling flow inside the last stable orbit of a thin disc around a Kerr black hole. The thickness of such a flow is determined primarily by the vertical stress created by radial and azimuthal magnetic fields. The thickness is predicted to oscillate vertically around its equilibrium value determined by the magnetic field balance with gravity. For thin discs, this thickness is much larger than that of the accretion disc itself. Numerical simulations with HARM2d show the vertical structure is more complicated. In particular, magnetically supported disc seems to be unstable to segregation of matter into thinner streams with the vertical scale determined by thermal pressure or other processes.
Highly supercritical accretion discs are probable sources of dense optically thick axisymmetric winds. We introduce a new approach based on diffusion approximation radiative transfer in a funnel geometry and obtain an analytical solution for the ener
gy density distribution inside the wind assuming that all the mass, momentum and energy are injected well inside the spherization radius. This allows to derive the spectrum of emergent emission for various inclination angles. We show that self-irradiation effects play an important role altering the temperature of the outcoming radiation by about 20% and the apparent X-ray luminosity by a factor of 2-3. The model has been successfully applied to two ULXs. The basic properties of the high ionization HII-regions found around some ULXs are also easily reproduced in our assumptions.
We report the results of our observations of the nebular complex MH9/10/11, associated with the ULX HoIX X-1, with scanning Fabry-Perot Interferometer. Two regions differing by their kinematics and line ratios may be distinguished, roughly correspond
ing to the bubble nebula MH9/10 and fainter HII-region MH11. For MH9/10 we find the expansion rate of 20-70km/s that is different for the approaching and receding parts. MH11 is characterised by very low velocity dispersion (less than or about 15km/s) and nearly constant line-of-sight velocities. Properties of MH11 may be explained by photoionization of gas with hydrogen density of about 0.2cm^-3. Luminosity required for that should be of the order of 10^39erg/s. Similar power source is required to explain the expansion rate of MH9/10. Modelling results also indicate that oxygen abundance in MH11 is about solar.
