Metallicity-dependendent kinematics and morphology of the Milky Way bulge

TL;DR

This study employs chemo-dynamic simulations to explore how metallicity influences the morphology and kinematics of the Milky Way's bulge, revealing complex stellar components and their interrelations.

Contribution

It introduces a detailed chemo-dynamic model of the Milky Way bulge that links metallicity with morphology and kinematics, aligning well with observations.

Findings

Multiple stellar components coexist in the bulge region.

Strong correlations between metallicity, kinematics, and morphology are identified.

The model results agree qualitatively with observational data.

Abstract

We use N-body chemo-dynamic simulations to study the coupling between morphology, kinematics and metallicity of the bar/bulge region of our Galaxy. We make qualitative comparisons of our results with available observations and find very good agreement. We conclude that this region is complex, since it comprises several stellar components with different properties -- i.e. a boxy/peanut bulge, thin and thick disc components, and, to lesser extents, a disky pseudobulge, a stellar halo and a small classical bulge -- all cohabiting in dynamical equilibrium. Our models show strong links between kinematics and metallicity, or morphology and metallicity, as already suggested by a number of recent observations. We discuss and explain these links.