Origin of ultra-high energy cosmic rays

Determine the astrophysical sources that produce ultra-high energy cosmic rays (UHECRs).

Background

The paper studies the Amaterasu event in the broader context of UHECR source identification. Despite extensive observational and modeling efforts, deflections in Galactic and extragalactic magnetic fields and limited statistics at the highest energies hinder definitive source associations.

This longstanding uncertainty motivates the paper’s simulation-based inference approach, which constrains potential source locations under realistic propagation effects, but the fundamental problem of identifying the classes of objects responsible for UHECR production remains unresolved.