Order and chaos in a triaxial galaxy model with a dark halo component

TL;DR

This study investigates how the presence and properties of a dark halo influence the regularity or chaos of stellar orbits in a triaxial galaxy, introducing a new rapid indicator for orbit classification.

Contribution

The paper introduces the total angular momentum Ltot as a new, efficient chaos indicator and analyzes its effectiveness compared to existing methods.

Findings

Chaotic orbit percentage decreases exponentially with increasing dark halo mass.

Chaotic orbit percentage increases linearly with the scale length of the dark halo.

Ltot is a fast and reliable indicator for orbit classification in galactic potentials.

Abstract

We study the regular or chaotic nature of orbits in a 3D potential describing a triaxial galaxy surrounded by a spherical dark halo component. Our numerical calculations show, that the percentage of chaotic orbits decreases exponentially, as the mass of the dark halo increases. A linear increase of the percentage of the chaotic orbits was observed, as the scale length of the dark halo component increases. In order to distinguish between regular and chaotic character of orbits, we use the total angular momentum Ltot, as a new indicator. Comparison of this new dynamical parameter, with other, previously used chaos indicators, shows that the Ltot gives very fast and reliable results in order to detect the character of orbits in galactic potentials.