Kinematic effects of tidal interaction on galaxy rotation curves

We use self-consistent N-body models in conjunction with models of test particles moving in galaxy potentials to explore the initial effects of interactions on the rotation curves of spiral galaxies. Using nearly self-consistent disk/bulge/halo galaxy models, we simulate the first pass of galaxies on nearly parabolic orbits; we vary orbit inclinations, galaxy halo masses, and impact parameters. For each simulation, we mimic observed rotation curves of the model galaxies. Transient interaction-induced features of the curves include distinctly rising or falling profiles at large radii and pronounced bumps in the central regions. Remarkably similar features occur in our statistical sample of optical emission-line rotation curves of spiral galaxies in tight pairs and n-tuples.