Unveiling the Origin of the Fermi Bubbles

TL;DR

This paper reviews current understanding and future directions in uncovering the origin of the Fermi bubbles, giant gamma-ray structures in the Milky Way that inform cosmic-ray and Galactic magnetic field studies.

Contribution

It provides a comprehensive overview of observational and theoretical efforts to understand the formation mechanism of the Fermi bubbles.

Findings

Summarizes current theories on Fermi bubble formation

Highlights key observational constraints

Discusses potential future research directions

Abstract

The Fermi bubbles, two giant structures above and below the Galactic center (GC), are among the most important discoveries of the Fermi Gamma-ray Space Telescope. Studying their physical origin has been providing valuable insights into cosmic-ray transport, the Galactic magnetic field, and past activity at the GC in the Milky Way galaxy. Despite their importance, the formation mechanism of the bubbles is still elusive. Over the past few years there have been numerous efforts, both observational and theoretical, to uncover the nature of the bubbles. In this article, we present an overview of the current status of our understanding of the bubbles' origin, and discuss possible future directions that will help to distinguish different scenarios of bubble formation.