Ultra-high energy cosmic rays deflection by the Intergalactic Magnetic Field

TL;DR

This paper demonstrates that extragalactic magnetic bubbles, formed by galaxy feedback processes, significantly deflect ultra-high energy cosmic rays, affecting source identification.

Contribution

It introduces a novel extragalactic deflection mechanism independent of initial magnetic field conditions, based on simulations of galaxy feedback effects.

Findings

Approximately half of 10^20 eV protons are deflected by 1° or more.

Deflections can reach up to 20-30°, impacting source localization.

Extragalactic magnetic bubbles play a crucial role in UHECR deflections.

Abstract

The origin and composition of ultra-high energy cosmic rays (UHECRs) remain a mystery. The common lore is that UHECRs are deflected from their primary directions by the Galactic and extragalactic magnetic fields. Here we describe an extragalactic contribution to the deflection of UHECRs that does not depend on the strength and orientation of the initial seed field. Using the IllustrisTNG simulations, we show that outflow-driven magnetic bubbles created by feedback processes during galaxy formation deflect approximately half of all $10^{20}$ eV protons by $1^{\circ}$ or more, and up to $20$-$30^{\circ}$. This implies that the deflection in the intergalactic medium must be taken into account in order to identify the sources of UHECRs.