The UHECR spectrum measured at the Pierre Auger Observatory and its astrophysical implications

TL;DR

This paper reports improved measurements of the ultra-high-energy cosmic ray spectrum from the Pierre Auger Observatory, highlighting spectral features and discussing their astrophysical implications based on extensive data collection since 2004.

Contribution

It presents new, more precise measurements of the UHECR spectrum using hybrid and surface detector data, enhancing understanding of spectral features and their astrophysical significance.

Findings

Enhanced measurement precision of the UHECR spectrum

Identification of spectral features in the energy distribution

Implications for cosmic ray astrophysics

Abstract

The Southern part of the Pierre Auger Observatory is nearing completion, and has been in stable operation since January 2004 while it has grown in size. The large sample of data collected so far has led to a significant improvement in the measurement of the energy spectrum of UHE cosmic rays over that previously reported by the Pierre Auger Observatory, both in statistics and in systematic uncertainties. We summarize two measurements of the energy spectrum, one based on the high-statistics surface detector data, and the other of the hybrid data, where the precision of the fluorescence measurements is enhanced by additional information from the surface array. The complementarity of the two approaches is emphasized and results are compared. Possible astrophysical implications of our measurements, and in particular the presence of spectral features, are discussed.