Simulations of Gas Flow from a Galactic Disk to the BH - dominated Central Disk

With a help of hydrodynamical models, we explore fundamental modes of gas flow in central parts of a galaxy potential with non-axisymmetric perturbations of various strengths. Our grid-based algorithm allows us to get a detailed picture of gas dynamics down to about 10 pc from the galaxy center, where the central black hole becomes dominant. Gas inflow in a bar with an Inner Lindblad Resonance often stops at the nuclear ring. We find that embedded bars in resonant coupling are unlikely to increase the inflow, but for certain gas parameters in a single bar, inflow to the center develops in a spiral shock, similar to the patterns observed in nuclear discs of real galaxies. The spiral pattern persists for very weak non-axisymmetries of the potential.