Large-scale anisotropies of ultra-high-energy cosmic rays measured at the Pierre Auger Observatory

TL;DR

This paper reviews 19 years of data from the Pierre Auger Observatory, revealing large-scale anisotropies in ultra-high-energy cosmic rays that suggest an extragalactic origin for particles above 8 EeV.

Contribution

It provides a comprehensive overview of large-scale anisotropy studies in ultra-high-energy cosmic rays using extensive data from the Pierre Auger Observatory, including recent findings.

Findings

Detection of a dipolar anisotropy above 8 EeV with 6.8 sigma significance

Evidence supporting an extragalactic origin of ultra-high-energy cosmic rays above 8 EeV

Analysis of anisotropies across a wide energy range from 0.03 to 32 EeV

Abstract

Measurements of anisotropies in the arrival directions of ultra-high-energy cosmic rays are crucial to pinpoint their sources, which are yet to be discovered. A dipolar anisotropy in right ascension above 8~EeV has been detected by the Pierre Auger Observatory with a significance of $6.8 \sigma$. The direction of the dipole suggests an extragalactic origin of ultra-high-energy cosmic rays above those energies. In this contribution, we provide an overview of the studies on large-scale anisotropies in the arrival directions of ultra-high-energy cosmic rays measured at the Pierre Auger Observatory with energy thresholds from $\sim 0.03$~EeV up to $32$~EeV and we present and discuss the recent results achieved with the latest available dataset, which includes 19 years of operations -- resulting in a total exposure of 123,000~km$^2$~sr~yr and nearly 50,000 events above 8~EeV.