Properties of the Galactic Bar from Hydrodynamical Simulations

Abstract

It is well known that the existence of H I and CO gas at “forbidden” velocities in longitude-velocity (l-V) diagrams of the inner Galaxy (e.g. Liszt & Burton 1980, Liszt 1992) is inconsistent with circular motion in an axisymmetric potential. Gas flow in a barred potential could be consistent with the observations, however. We have compared the observations to 2-D hydrodynamical simulations of gas flows in a family of barred potentials. The gas flow pattern is very sensitive to the assumed potential, and the l-V distribution of cool gas in the inner Galaxy places strong constraints on several parameters of the Milky Way bar.