Self-consistent modelling of the Milky Way structure using live potentials

TL;DR

This paper develops and compares 15 dynamic Milky Way-like galaxy models using the AREPO code, successfully reproducing key observed structures and motions of our Galaxy to better understand its interstellar medium and star formation processes.

Contribution

It introduces a suite of self-consistent, dynamically evolving MW-type galaxy models that accurately mimic observed galactic features, improving upon previous static or analytic potential models.

Findings

Best-fitting model reproduces the Galactic bar with pattern speed 30 km/s/kpc

Model captures large streaming motions around spiral arms

Shows strong radial motions beyond the inner bar

Abstract

To advance our understanding of the evolution of the interstellar medium (ISM) of our Galaxy, numerical models of Milky Way (MW) type galaxies are widely used. However, most models only vaguely resemble the MW (e.g. in total mass), and often use imposed analytic potentials (which cannot evolve dynamically). This poses a problem in asserting their applicability for the interpretation of observations of our own Galaxy. The goal of this work is to identify a numerical model that is not only a MW-type galaxy, but one that can mimic some of the main observed structures of our Galaxy, using dynamically evolving potentials, so that it can be used as a base model to study the ISM cycle in a galaxy like our own. This paper introduces a suite of 15 MW-type galaxy models developed using the {\sc arepo} numerical code, that are compared to Galactic observations of $^{12}$CO and \ion{H}{I} emission via longitude-velocity plots, from where we extract and compare the skeletons of major galactic features and the terminal gas velocities. We found that our best-fitting model to the overall structure, also reproduces some of the more specific observed features of the MW, including a bar with a pattern speed of $30.0 \pm 0.2$ km\,s$^{-1}$\,kpc$^{-1}$, a bar half-length of $3.2 \pm 0.8$\,kpc. Our model shows large streaming motions around spiral arms, and strong radial motions well beyond the inner bar. This model highlights the complex motions of a dynamic MW-type galaxy and has the potential to offer valuable insight into how our Galaxy regulates the ISM and star formation.