Gas dynamics in the Galactic bar region from N-body and SPH simulations

Abstract

Self-consistent hybrid N-body and SPH simulations are used to give a new and coherent interpretation of the main features standing out from the HI and CO longitude-velocity observations within the Galactic bar. In particular, the traces of the gas associated to the Milky Way's dustlanes can be reliably identified and the 3-kpc arm appears as a gaseous stream rather than a density wave. The bar and the gaseous nuclear ring in the simulations undergo synchronised and long lived oscillations around the centre of mass, and the gas flow always remains non-stationary, suggesting a transient nature of the observed gas kinematics.