Asymmetric warps in disk galaxies: dependence on dark matter halo

Abstract

Recent observations have shown that most of the warps in the disk galaxies are asymmetric. However there exists no generic mechanism to generate these asymmetries in warps. We have shown that a rich variety of possible asymmetries in the z-distribution of the spiral galaxies can naturally arise due to a dynamical wave interference between the first two bending modes i.e. bowl-shaped mode(m=0) and S-shaped warping mode(m=1) in the galactic disk embedded in a dark matter halo. We show that the asymmetric warps are more pronounced when the dark matter content within the optical disk is lower as in early-type galaxies.