The Bar-Halo Interaction in SB Galaxies

We describe fully self-consistent N-body experiments of barred galaxies with massive halos. A rotating bar is braked through dynamical friction with the halo, which occurs on a short time scale when the central density of the halo is high. On the other hand, friction is weak in a model with a central halo density low enough that the disk dominates the rotation curve in the inner parts; this model supports a fast bar for a Hubble time. We conclude that real barred galaxies in which the bar rotates rapidly, which is believed to be the rule, must have close to maximum disks.