Introducing the Rhea simulations of Milky-Way-like galaxies I: Effect of gravitational potential on morphology and star formation

TL;DR

This paper presents Rhea simulations of Milky Way-like galaxies to study how different gravitational potentials affect galaxy morphology and star formation, highlighting the limited impact of spiral arms and the significant influence of the galactic bar.

Contribution

The study introduces detailed Rhea simulations with varying gravitational potentials to analyze their effects on galaxy structure and star formation, providing insights into the roles of spiral arms and bars.

Findings

Galactic bar influences star formation within 2.5 kpc.

Spiral arm potential has minimal impact on star formation.

Overall morphology is similar despite different potentials.

Abstract

The Milky Way is a complex ecosystem, for which we can obtain detailed observations probing the physical mechanisms determining the interstellar medium. For a detailed comparison with observations, and to provide theories for missing observables, we need to model the Milky Way as closely as possible. However, details of the Galactic structure are not fully defined by observations, raising the need for more generalized models. With the Rhea simulations we present a set of Milky Way like simulations, containing detailed physics of the interstellar medium, as well as star formation and stellar feedback. We conduct two simulations that differ in the gravitational potential: one fitted to several structural details derived from observations, the other just reproducing the most basic quantities. We find little difference in the overall morphology except for the bar region, which funnels gas towards the Galactic inner region and therefore prevents quenching in the center. Despite differences with galacto-centric radius, the global star formation rate is almost identical in both setups. A spiral arm potential does not influence properties of groups of formed stars. A bar potential, however, lowers size and formation time of those groups. We therefore conclude for a spiral arm potential to have little influence on star formation in the Galaxy, except for producing long-lived spiral structures instead of transient ones. A Galactic bar potential has noticeable influence on star formation mainly within the innermost 2.5kpc.