The Stellar Kinematics of Extragalactic Bulges

TL;DR

This review discusses the evolving understanding of galactic bulges' stellar kinematics, highlighting their complex structures and the impact of advanced spectroscopy on revealing their dynamical states and substructures.

Contribution

It synthesizes recent developments in the study of extragalactic bulge kinematics, emphasizing the role of spectroscopy in uncovering their complexity and dynamical properties.

Findings

Galactic bulges exhibit diverse photometric and kinematic substructures.

Spectroscopy has significantly advanced understanding of bulge dynamics.

Bulge properties are interconnected with morphology and stellar populations.

Abstract

Galactic bulges are complex systems. Once thought to be small-scale versions of elliptical galaxies, advances in astronomical instrumentation (spectroscopy in particular) has revealed a wealth of photometric and kinematic substructure in otherwise simple-looking components. This review provides an overview of how our perspective on galactic bulges has changed over the years. While it is mainly focused on aspects related to the dynamical state of their stars, there will be natural connections to other properties (e.g. morphology, stellar populations) discussed in other reviews in this volume.