Dynamics of disks and warps

Abstract

This chapter reviews theoretical work on the stellar dynamics of galaxy disks.All the known collective global instabilities are identified and their mechanismsdescribed in terms of local wave mechanics. A detailed discussion of warps andother bending waves is also given. The structure of bars in galaxies, and theireffect on galaxy evolution, is now reasonably well understood, but there is still noconvincing explanation for their origin and frequency. Spiral patterns havelong presented a special challenge, and ideas and recent developments arereviewed. Other topics include scattering of disk stars and the survival of thindisks.