Large-scale Gas Dynamics in the Milky Way

Abstract

We present new gas flow models for the Milky Way inside the solar circle. Using a mass model derived from the COBE/DIRBE maps and clump giant star counts, and using a parametric model for the spiral arm pattern in the disk, we calculate the gas flow and compare with 12CO observations. We find that models with 4 spiral arms fit the observations better then 2-armed models. We also find that models with separate pattern speeds for the bar and spiral arms can explain the gas flow in the bar corotation region better than single-pattern speed models.

invited talk, 7 pages, LaTeX, full resolution version available at http://www.astro.unibas.ch/~ppe/papers/mw-boston.ps.gz, to appear in Milky Way Surveys: The Structure and Evolution of Our Galaxy, eds. D. Clemens, T. Brainerd, R. Shah