Axion-like particles: possible hints and constraints from the high-energy Universe

TL;DR

This paper explores how axion-like particles (ALPs) could influence high-energy astrophysical phenomena, offering potential hints of their existence and setting constraints based on cosmic gamma-ray observations and magnetic turbulence effects.

Contribution

It discusses the potential observable effects of ALPs in the high-energy Universe and how these effects can be used to detect or constrain ALP properties.

Findings

Hints for ALP existence from gamma-ray transparency

Constraints on ALP mass and coupling from astrophysical magnetic turbulence

Implications for future high-energy observations

Abstract

The high-energy Universe is potentially a great laboratory for searching new light bosons such as axion-like particles (ALPs). Cosmic sources are indeed the scene of violent phenomena that involve strong magnetic field and/or very long baselines, where the effects of the mixing of photons with ALPs could lead to observable effects. Two examples are archetypal of this fact, that are the Universe opacity to gamma-rays and the imprints of astrophysical magnetic turbulence in the energy spectra of high-energy sources. In the first case, hints for the existence of ALPs can be proposed whereas the second one is used to put constraints on the ALP mass and coupling to photons.