Tidal torques and galactic warps

Abstract%We study the evolution of galactic disks subject to tidal torques motivated by cosmological N-body simulations using analytic and numerical techniques. We find that self-gravitating disks subject to these torques resemble observed warped galaxies. The warps develop at a local surface density of 70 M⊙ pc-2 and move out through the disk at a rate that depends on the surface density of the disk.