Structure of merger remnants. V. Kinematics

In this paper we report on a study of the kinematics of merger remnants. We have performed a series of numerical simulations of galaxy mergers, using a variety of orbital geometries and progenitor galaxies. Our analysis highlights three aspects of the kinematics of remnants: the misalignment of the total angular momentum of the luminous matter with respect to the minor axis of its spatial distribution; rotation curves along the major axis; and the distribution of luminous particles over the various allowed orbital families. By comparing the results from the various simulations, we learn how encounter geometry and the structure of the progenitors can affect the velocity distribution of the remnants. The encounter geometry, the structure of the progenitors, and the shape of the remnant play deciding roles in the distribution of angular momentum over the remnant, and therefore in the final velocity distribution. We have employed a hybrid of two numerical techniques in our investigation. First, the encounter and the evolution of the remnant to equilibrium are simulated using a hierarchical tree algorithm. Once the remnant has settled down, we use a self-consistent field approach to study its orbit structure, thereby mitigating the scattering of particles between orbit families owing to two-body interactions. With this hybrid, a reliable determination of the orbital distribution of particles is practical.