2D kinematics of simulated disc merger remnants

Abstract

We present a two-dimensional kinematic analysis for a sample of simulated binary disc merger remnants with mass ratios 1:1 and 3:1. For the progenitor discs we used pure stellar models as well as models with 10% of their mass in gas. A multitude of phenomena also observed in real galaxies are found in the simulations. These include misaligned rotation, embedded discs, gas rings, counter-rotating cores and kinematic misaligned discs. Using the 2D maps we illustrate projection effects and the change in properties of a merger remnant when gas is included in the merger. We find that kinematic peculiar subsystems are preferably formed in equal mass mergers. Equal-mass collisionless remnants can show almost no rotation, regular rotation or strong kinematic misalignment. The inclusion of gas makes the remnants appear more round(1:1) and axisymmetric(3:1). Counter-Rotating Cores (CRCs) are almost exclusively formed in equal-mass mergers with a dissipational component. 3:1 remnants show a much more regular structure. We quantify these properties by applying the kinemetric methods recently developed by Krajnovi_s18_s14c et al. This work will help to understand observations of elliptical galaxies with 2D field spectrographs, like SAURON.