Effect of Multipole Moments in the Weak Field Limit of a Black Hole Plus Halo Potential

TL;DR

This study investigates how quadrupole and octupole moments influence the motion of particles near a black hole with a halo, revealing significant effects on trajectory types and phase space structure.

Contribution

It introduces a detailed analysis of multipole effects on particle dynamics near black holes with halos, using basin diagrams and phase space analysis.

Findings

Multipole moments significantly affect particle trajectories.

Phase space is dominated by collision and escape orbits.

Different types of bounded motion are distinguished.

Abstract

In this paper, we consider a Newtonian system whose relativistic counterpart describes a superimposed halo with a black hole. Our aim is to determine how the quadrupole and octupole moments affect the nature of the motion of a test particle, moving in the close vicinity of the black hole. The different types of trajectories for the test particle are mainly classified as bounded, collisional, and escaping, by using modern color-coded basin diagrams. Moreover, an additional analysis is carried out for distinguishing between the different types of bounded motion (regular, sticky, and chaotic). Our results strongly indicate that the multipole moments, along with the total orbital energy, highly affect the final state of the test particle, while at the same time the basin geometry of the phase space tends to be highly dominated by collision and escape orbits.