# Interactions of Cosmic Rays around the Universe. Models for UHECR data interpretation

## TL;DR

This paper reviews models for interpreting ultra high energy cosmic ray data, focusing on their interactions with astrophysical environments and intergalactic photon fields, highlighting uncertainties affecting their propagation and detection.

## Contribution

It introduces comprehensive models that incorporate source interactions and intergalactic photon fields to better interpret UHECR observations, addressing key uncertainties.

## Key findings

- Interactions depend on photon energy and environment
- Uncertainties in background spectrum affect propagation models
- Models improve understanding of UHECR origins and behavior

## Abstract

Ultra high energy cosmic rays (UHECRs) are expected to be accelerated in astrophysical sources and to travel through extragalactic space before hitting the Earth atmosphere. They interact both with the environment in the source and with the intergalactic photon fields they encounter, causing different processes at various scales depending on the photon energy in the nucleus rest frame. UHECR interactions are sensitive to uncertainties in the extragalactic background spectrum and in the photo-disintegration models.