# Fermi Bubbles: an Elephant in the Gamma-ray Sky

## TL;DR

The paper reviews the Fermi bubbles' gamma-ray features, discusses leptonic and hadronic emission models, and emphasizes the need for multi-wavelength observations to understand their origin.

## Contribution

It provides a comparative overview of leptonic and hadronic gamma-ray production mechanisms for the Fermi bubbles and highlights the importance of multi-messenger data.

## Key findings

- Gamma-ray emission models are crucial to understanding the bubbles.
- Multi-wavelength observations are essential for resolving their origin.
- Current gamma-ray data alone are insufficient to determine the bubbles' nature.

## Abstract

The Fermi bubbles are one of the most remarkable features in the gamma-ray sky revealed by the Fermi Large Area Telescope (LAT). The nature of the gamma-ray emission and the origin of the bubbles are still open questions. In this note, we will review some basic features of leptonic and hadronic modes of gamma-ray production. At the moment, gamma rays are our best method to study the bubbles, but in order to resolve the origin of the bubbles multi-wavelength and multi-messenger observations will be crucial.