The Galactic Bar

TL;DR

This paper reviews the structure and dynamics of the Milky Way's bar and bulge, highlighting recent star count analyses and the possible presence of a disky pseudo-bulge, with implications for galactic evolution.

Contribution

It presents new insights into the shape and structure of the Galactic bulge and bar, including evidence for a peanut-shaped bulge and a potential transition to a long bar.

Findings

Identification of a pronounced peanut-shaped bulge.

Evidence for a continuous transition in vertical scale-height.

Discussion of the presence of an inner disky pseudo-bulge.

Abstract

The Milky Way's bar dominates the orbits of stars and the flow of cold gas in the inner Galaxy, and is therefore of major importance for Milky Way dynamical studies in the Gaia era. Here we discuss the pronounced peanut shape of the Galactic bulge that has resulted from recent star count analysis, in particular from the VVV survey. We also discuss the question whether the Milky Way has an inner disky pseudo-bulge, and show preliminary evidence for a continuous transition in vertical scale-height from the peanut bulge-bar to the planar long bar.