Orbital structure in N-Body models of barred galaxies

TL;DR

This study analyzes the orbital structure of a simulated barred galaxy, revealing that 60% of orbits are chaotic and identifying key orbit types that support the galaxy's bar and boxy shape.

Contribution

It provides a detailed classification of orbital types in a self-consistent N-body barred galaxy model, highlighting the role of chaotic and resonant orbits.

Findings

60% of orbits are chaotic

Real particles avoid non-supporting orbits

Weakly chaotic orbits support bar boxiness

Abstract

We study the orbital structure of a self-consistent N-body equilibrium configuration of a barred galaxy constructed from cosmological initial conditions. The value of its spin parameter L is near the observed value of our Galaxy L=0.22. We classify the orbits in regular and chaotic using a combination of two different methods and find 60% of them to be chaotic. We examine the phase space using projections of the 4D surfaces of section for test particles as well as for real N-body particles. The real particles are not uniformly distributed in the whole phase space but they avoid orbits that do not support the bar. We use frequency analysis for the regular orbits as well as for the chaotic ones to classify certain types of orbits of our self-consistent system. We find the main resonant orbits and their statistical weight in supporting the shape of the bar and we emphasize the role of weakly chaotic orbits in supporting the boxiness at the end of the bar.