Constraining gamma-ray propagation on cosmic distances

TL;DR

This paper reviews how gamma-ray observations over cosmological distances inform us about the universe's diffuse radiation, magnetic fields, and potential new physics, emphasizing the role of the Cherenkov Telescope Array.

Contribution

It provides a comprehensive overview of gamma-ray propagation studies and highlights the significance of CTA observations for future cosmological insights.

Findings

Gamma-ray observations constrain diffuse radiation fields.

Observations suggest large-scale cosmic magnetism.

Gamma-ray data may reveal physics beyond standard models.

Abstract

Studying the propagation of gamma rays on cosmological distances encompasses a variety of scientific fields, focusing on diffuse radiation fields such as the extragalactic background light, on the probe of the magnetism of the Universe on large scales, and on physics beyond the standard models of cosmology and particle physics. The measurements, constraints and hints from observations of gamma-ray blazars by airborne and ground-based instruments are briefly reviewed. These observations point to gamma-ray cosmology as one of the major science cases of the Cherenkov Telescope Array, CTA.