Dynamical Parameters for AM 0644−741

Abstract

We present a simulation match to the 2004 Hubble Heritage high-resolution optical images of AM 0644-741. In N-body/smoothed particle hydrodynamics (SPH) simulations of AM 0644-741, we recreate the star formation features, as well as the underlying kinematics. Our simulations contain sufficient numerical density to accurately distinguish the overlapping/double ring, as well as the off-center nucleus seen in the radio observations of Higdon & Wallin and the young stellar features noted in the Space Telescope Science Institute Heritage observation. Derived star formation rates for the ring and nucleus match the observed star formation features, particularly when using a dρ/dt star formation formulation. Kinematic comparison with the results of Few and collaborators yields a match for the ring velocities but not necessarily the companion. We note that the gravity and gas dynamics, modeled by N-body plus SPH, dominate over feedback from stellar evolution effects (modeled using a variety of Schmidt-type parameters), resolving the dilemma posed by Cox and coworkers. Comparing our simulation to reality gives us insight into the ring longevity and likely generative impact scenario, reaffirming the collisional origins of this ring.