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

TL;DR

This study uses a simplified dynamical model to analyze how different parameters influence orbit types in barred galaxy centers, revealing diverse orbital families supporting galactic structures.

Contribution

It introduces a model that identifies various regular and chaotic orbit types, challenging the traditional dominance of the x1 family in barred galaxies.

Findings

Sparse nuclei and fast bars support galactic bars.

Dense nuclei and slow bars favor nuclear rings.

Multiple resonant orbit types can sustain the bar structure.

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 x1 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.