Stability of general relativistic Miyamoto-Nagai galaxies

TL;DR

This paper investigates the stability of a general relativistic Miyamoto-Nagai galaxy model, revealing that disk thickness influences stability and that flatter galaxies tend to develop complex structures.

Contribution

It introduces a relativistic version of the Miyamoto-Nagai galaxy model and analyzes its stability under perturbations, highlighting the role of disk thickness.

Findings

Flat galaxies have more unstable modes.

Thicker galaxies are more stable.

Stability correlates with disk thickness.

Abstract

The stability of a recently proposed general relativistic model of galaxies is studied in some detail. This model is a general relativistic version of the well known Miyamoto-Nagai model that represents well a thick galactic disk. The stability of the disk is investigated under a general first order perturbation keeping the spacetime metric frozen (no gravitational radiation is taken into account). We find that the stability is associated with the thickness of the disk. We have that flat galaxies have more not-stable modes than the thick ones i.e., flat galaxies have a tendency to form more complex structures like rings, bars and spiral arms.