Astrophysical source of the Amaterasu particle

Identify the location of the astrophysical source that produced the Amaterasu ultra-high-energy cosmic-ray event detected by the Telescope Array, given its measured energy and arrival direction.

Background

The Amaterasu particle is the second-highest energy cosmic ray ever detected and was observed by the Telescope Array with a precisely measured arrival direction. Prior analyses suggest its direction lies toward the Local Void, with no obvious nearby counterpart, leading to multiple hypotheses including starburst galaxies, active galactic nuclei, and transient sources.

This paper employs 3D CRPropa simulations and approximate Bayesian computation to map posterior source regions under uncertainties in magnetic fields, composition, and energy scale, but the exact source location remains unresolved.