Simulating non-axisymmetric flows in disk galaxies

Abstract

Context. We present a two-step method to simulate and study non-circular motions in strongly barred galaxies. The first step is to constrain the initial parameters using a Bayesian analysis of each galaxy’s azimuthally averaged rotation curve, the 3.6 μm surface brightness, and the gas surface density. The second step is to generate equilibrium models using the GalactICS code and evolve them via GADGET-2. Aims. The bar strengths and mock velocity maps of the resulting snapshots are compared to observations in order to determine the best representation of the galaxy. Methods. We apply our method to the unbarred galaxy NGC 3621 and the barred galaxies NGC 1300 and NGC 1530. NGC 3621 provides a validation of our method of generating initial conditions. NGC 1530 has an intermediate bar orientation that allows for a comparison to DiskFit. Finally NGC 1300 has a bar oriented parallel to the galaxy’s major axis, where other algorithms tend to fail. Results. Our models for NGC 3621 and NGC 1530 are comparable to those obtained using commonly available algorithms. Moreover, we produce one of the first mass distribution models for NGC 1300.