GALACTIC DISK WARPS

Warped equilibrium configurations of galactic disks embedded in flattened haloes are considered. The relevant torques are calculated in their full nonlinearity, extending the results of linear-mode calculations. It is shown that for two specific examples, NGC 2841 and M33, it is possible to reproduce closely the observed warp shapes with these models. It is further demonstrated that the observed shapes of a galaxy's warp and rotation curve do not suffice to determine the disk mass uniquely, but can only provide upper limits on the disk-to-halo mass ratio. In the case of M33, this limit is about one-third of a maximal disk decomposition of the rotation curve. Qualitative differences between the linear theory and the present work are discussed.