Modelling Spiral Galaxies

TL;DR

This paper introduces a new modeling technique for spiral galaxies that produces self-consistent, observation-matching dynamics, including spiral structures and velocity dispersions, with implications for dark matter distribution.

Contribution

The paper presents a novel method to model spiral galaxies with self-consistent dynamics, incorporating a dynamical interstellar medium and explaining observed features like spiral arms and velocity dispersions.

Findings

A four-arm spiral structure similar to the Milky Way's observed ISM emerges in simulations.

Jeans instability explains the observed velocity dispersion of atomic hydrogen.

The model supports the Bosma effect with baryonic and dark matter in the disc.

Abstract

We develop a new technique to equip models of spiral galaxies with self-consistent dynamics that match observations. We apply our technique and construct a model for the Milky Way with a dynamical interstellar medium (ISM). In simulations a four-arm spiral structure emerges from this model that is similar to the one observed in the Milky Way's ISM. Further, in our model the Jeans instability offers an explanation for the observed velocity dispersion of atomic hydrogen in the ISM; this instability vanishes from our model if we choose a velocity dispersion just above the observed one. Our model uses baryonic, dark matter, which resides in the disc and is dynamically cold. This makes our model a typical example for the Bosma effect.