Warped Galaxies from Misaligned Angular Momenta

A galaxy disk embedded in a rotating halo experiences a dynamical frictionforce which causes it to warp when the angular momentum axes of the disk andhalo are misaligned. Our fully self-consistent simulations of this processinduce long-lived warps in the disk which mimic Briggs's rules of warpbehavior. They also demonstrate that random motion within the disk addssignificantly to its stiffness. Moreover, warps generated in this way have nowinding problem and are more pronounced in the extended \h1 disk. As emphasizedby Binney and his co-workers, angular momentum misalignments, which areexpected in hierarchical models of galaxy formation, can account for the highfraction of warped galaxies. Our simulations exemplify the role of misalignedspins in warp formation even when the halo density is not significantlyflattened.Comment: 6 pages, 5 figures. Accepted for publication in Ap.J.