Photon-axion mixing and ultra-high-energy cosmic rays from BL Lac type objects -- Shining light through the Universe

TL;DR

This paper explores how photon-axion conversion in cosmic magnetic fields could explain the detection of ultra-high-energy cosmic rays and TeV photons from distant BL Lac objects, providing a new perspective on astrophysical particle propagation.

Contribution

It proposes a mechanism involving photon-axion mixing in astrophysical magnetic fields to explain observations of ultra-high-energy cosmic rays and TeV photons from distant sources.

Findings

Photon-axion conversion can account for observed ultra-high-energy cosmic rays.

Axions may explain the transparency of the universe to TeV photons.

The model links particle physics with astrophysical observations.

Abstract

Photons may convert into axion like particles and back in the magnetic field of various astrophysical objects, including active galaxies, clusters of galaxies, intergalactic space and the Milky Way. This is a potential explanation for the candidate neutral ultra-high-energy (E>10^18 eV) particles from distant BL Lac type objects which have been observed by the High Resolution Fly's Eye experiment. Axions of the same mass and coupling may explain also TeV photons detected from distant blazars.