Measurements of cosmic rays at the highest energies with the Pierre Auger Observatory

TL;DR

This paper reports recent measurements from the Pierre Auger Observatory, including the cosmic ray energy spectrum, anisotropy searches, proton-air cross section, and mass composition, advancing understanding of ultra-high-energy cosmic rays.

Contribution

It provides new measurements of cosmic ray properties at the highest energies, including the first proton-air cross section around 10^{18} eV, and analyzes anisotropies and composition.

Findings

Energy spectrum features discussed

Anisotropy searches conducted without catalogues

First proton-air cross section measurement at 10^{18} eV

Abstract

This paper summarizes the status and the recent measurements from the Pierre Auger Observatory. The energy spectrum is described and its features discussed. We report searches for anisotropy of cosmic ray arrival directions on large scales and through correlation with catalogues of celestial objects. We also present the search for anisotropies in the data without the use of astronomical catalogues. The first measurement of the proton-air cross section around 10^{18} eV is discussed. Finally, the mass composition is addressed with measurements of the variation of the depth of shower maximum with energy and with the muon density at ground.