Determining the type of orbits in the central regions of barred galaxies

Abstract

We use a simple dynamical model which consists of a harmonic oscillator and a spherical component, in order to investigate the regular or chaotic character of orbits in a barred galaxy with a central spherically symmetric nucleus. Our aim is to explore how the basic parameters of the galactic system influence the nature of orbits, by computing in each case the percentage of chaotic orbits, as well as the percentages of different types of regular orbits. We also give emphasis to the types of regular orbits that support either the formation of nuclear rings or the barred structure of the galaxy. We provide evidence that the traditional x 1 orbital family does not always dominate in barred galaxy models since we found several other types of resonant orbits which can also support the barred structure. We also found that sparse enough nuclei, fast rotating bars and high energy models can support the galactic bars. On the other hand, weak bars, dense central nuclei, slowly rotating bars and low energy models favor the formation of nuclear rings. We also compare our results with previous related work.

Orbit classification in a disk galaxy model with a pseudo-Newtonian central black hole

“…In all cases, the value of the total orbital energy is fixed to E = −0.05, which corresponds to the maximum possible value of R coordinate (about 10 kpc for a typical disk galaxy (see e.g., Binney & Tremaine 2008)). We decided to keep fixed the value of the energy because its influence on the character of orbits moving in the meridional plane has already been revealed in Zotos (2016).…”