Ultra High Energy Cosmic Rays: origin and propagation

TL;DR

This paper reviews the challenges in understanding the origins and propagation of ultrahigh energy cosmic rays, discussing experimental results and models, highlighting the difficulty in identifying their sources due to attenuation effects.

Contribution

It provides a comprehensive overview of the current experimental findings and theoretical models related to the origin and propagation of ultrahigh energy cosmic rays.

Findings

Experimental results show no definitive source identification.

Attenuation limits the distance of potential sources.

Models are consistent with current observational data.

Abstract

We discuss the basic difficulties in understanding the origin of the highest energy particles in the Universe - the ultrahigh energy cosmic rays (UHECR). It is difficult to imagine the sources they are accelerated in. Because of the strong attenuation of UHECR on their propagation from the sources to us these sources should be at cosmologically short distance from us but are currently not identified. We also give information of the most recent experimental results including the ones reported at this conference and compare them to models of the UHECR origin.