Pattern speeds in barred spiral galaxies

Abstract

Current theoretical ideas of the pattern speeds of the bar and spiral arms in SB galaxies appear to conflict with the observational evidence. This difficulty can be avoided if the spiral arms have a lower pattern speed than the bar. We present evidence of multiple pattern speeds in our A-body simulations, and show that, though the spiral continually breaks from and reconnects to the bar, the morphology of the pattern at all times resembles that of barred galaxies in the sky. We briefly discuss how the gas might respond to the multiple patterns.