Title：Gas inflow patterns and nuclear rings in barred galaxies

Speaker：Juntai Shen, Research Fellow
Unit：Shanghai Astronomical Observatory
Time：2016.03.30（Wednesday） 14:30
Place：Physics Building 573, Haiyun Campus, Xiamen University
Abstract：Nuclear rings, dust lanes, and nuclear spirals are common structures in the inner region of barred galaxies, with their shapes and properties linked to the physical parameters of the galaxies. We use high-resolution hydrodynamical simulations to study gas inflow patterns in barred galaxies, with special attention on the nuclear rings. The location and thickness of nuclear rings are tightly correlated with galactic properties, such as the bar pattern speed and bulge central  ensity, within certain ranges. We identify the backbone of nuclear rings with a major orbital family of bars. The rings form  exactly at the radius where the residual angular momentum of inflowing gas balances the centrifugal force. We propose a  new simple method to predict the bar pattern speed for barred galaxies possessing a nuclear ring, without actually doing  simulations. We apply this method to some real galaxies and find that our predicted bar pattern speed compare reasonably well with other estimates. Our study may have important implications for using nuclear rings to measure the parameters of  real barred galaxies with detailed gas kinematics. I will also discuss the preliminary results of extending current hydrodynamical simulations to the Milky Way.