Effects of extragalactic magnetic field on the spectra of ultra-high-energy cosmic rays from jetted sources

TL;DR

This paper uses numerical simulations to explore how extragalactic magnetic fields and jet geometry influence the observed spectra of ultra-high-energy cosmic rays, revealing that emission geometry can significantly shape observational signatures.

Contribution

It demonstrates for the first time that emission geometry affects the spectral signatures of UHECR sources in a magnetized universe, providing new insights into detection conditions.

Findings

Emission geometry influences UHECR spectra under certain conditions.

Magnetic fields and jet orientation jointly affect observational signatures.

Simulation results highlight the importance of source geometry in UHECR studies.

Abstract

The origins and acceleration mechanisms of ultra-high-energy cosmic rays (UHECRs) are unknown. Many models attribute their extreme energies to powerful astrophysical jets. Understanding whether jet geometry -- specifically the opening angle and its orientation relative to Earth -- affects observational signatures is crucial for interpreting UHECR data. In this work, we perform numerical simulations of UHECR propagation in a magnetized universe to investigate the spectral signatures of jetted and nonjetted astrophysical sources. We demonstrate, for the first time, that under certain conditions, emission geometry can play a decisive role in shaping the observed spectrum of individual UHECR sources. These findings provide new insights into the conditions necessary for detecting UHECRs from jets, and highlight how the interplay between emission geometry and magnetic fields influences observed energy spectra.