Propagation of UHE protons through a magnetized large scale structure

TL;DR

This paper models how ultra-high-energy cosmic ray protons are deflected and delayed by intergalactic magnetic fields derived from large scale structure simulations, impacting their observed properties.

Contribution

It introduces a novel method to estimate extragalactic magnetic fields from gas flow properties in cosmological simulations for UHECR propagation studies.

Findings

Magnetic deflections can significantly alter UHECR trajectories.

Time delays depend on large scale structure and magnetic field strength.

Energy spectra are affected by interactions with cosmic background radiation.

Abstract

The propagation of UHECRs is affected by the intergalactic magnetic fields that were produced during the course of the large scale structure formation of the universe. We adopt a novel model where the large scale extragalactic magnetic fields (EGMF) are estimated from local dynamic properties of the gas flows in hydrodynamic simulations of a concordance LambdaCDM universe. With the model magnetic fields, we calculate the deflection angle, time delay and energy spectrum of protons with E > 10^{19} eV that are injected at cosmological sources and then travel through the large scale structure of the universe, losing the energy due to interactions with the cosmic background radiation. Implications of this study on the origin of UHECRs are discussed.