Pattern speeds in the Milky Way
  A brief review is given of different methods used to determine the pattern
speeds of the Galactic bar and spiral arms. The Galactic bar rotates rapidly,
with corotation about halfway between the Galactic center and the Sun, and
outer Lindblad resonance not far from the solar orbit, R0. The Galactic spiral
arms currently rotate with a distinctly slower pattern speed, such that
corotation is just outside R0. Both structures therefore seem dynamically
decoupled.
