Disks controlling chaos in a 3D dynamical model for elliptical galaxies

TL;DR

This paper demonstrates that disk components in elliptical galaxy models can effectively control chaos, with the introduction of a new parameter, S(w), to distinguish regular and chaotic orbits in 3D dynamical systems.

Contribution

The study introduces the S(w) spectrum as a new, efficient chaos indicator and shows how increasing disk mass reduces chaos in elliptical galaxy models.

Findings

Increasing disk mass reduces chaotic regions in phase space.

The S(w) spectrum effectively distinguishes regular from chaotic orbits.

Disks can act as controllers of chaos in elliptical galaxies.

Abstract

A 3D dynamical model with a quasi-homogeneous core and a disk component is used for the chaos control in the central parts of elliptical galaxy. Numerical experiments in the 2D system show a very complicated phase plane with a large chaotic sea, considerable sticky layers and a large number of islands, produced by secondary resonances. When the mass of the disk increases, the chaotic regions decrease gradually, and, finally, a new phase plane with only regular orbits appears. This evolution indicates that disks in elliptical galaxies can act as the chaos controllers. Starting from the results obtained in the 2D system, we locate the regions in the phase space of the 3D system, producing regular and chaotic orbits. For this we introduce and use a new dynamical parameter, the S(w) spectrum, which proves to be useful as a fast indicator and allows us to distinguish the regular motion from chaos in the 3D potentials. Other methods for detecting chaos are also discussed.