Magnetic horizons of ultra-high energy cosmic rays

TL;DR

This paper investigates how extragalactic magnetic fields affect the propagation of ultra-high energy cosmic rays, potentially creating a magnetic horizon that influences observed cosmic ray fluxes around 10^18 eV.

Contribution

It uses cosmological simulations to evaluate the existence and impact of magnetic horizons on cosmic ray propagation at ultra-high energies.

Findings

Magnetic fields can cause diffusive propagation of cosmic rays.

Propagation times can be comparable to the universe's age, affecting flux measurements.

Magnetic horizons may suppress cosmic ray flux at certain energies.

Abstract

The propagation of ultra-high energy cosmic rays in extragalactic magnetic fields can be diffusive, depending on the strength and properties of the fields. In some cases the propagation time of the particles can be comparable to the age of the universe, causing a suppression in the flux measured on Earth. In this work we use magnetic field distributions from cosmological simulations to assess the existence of a magnetic horizon at energies around 10$^{18}$ eV.