Related papers: The UHECR spectrum measured at the Pierre Auger Ob…

The Auger experiment was designed to study the high-energy cosmic rays by measuring the properties of the showers produced in the atmosphere. The Southern Auger Observatory has taken data since January 2004. Results on mass composition,…

The Pierre Auger Observatory has collected data for more than 15 years, accumulating the world's largest exposure to ultrahigh energy cosmic rays (UHECRs). The energy spectrum of the UHECRs has been measured up to $10^{20.2}$ eV, and their…

Ultra-high-energy cosmic rays (UHECR), of energy >10 EeV, arrive at the Earth regularly, but their sources, acceleration mechanisms, details of propagation through the universe, and particle composition remain mysteries. In addition, their…

We present the spectrum of cosmic rays with energies above 2.5 EeV measured at the Pierre Auger Observatory after 19 years of operation, covering the period before the AugerPrime upgrade. Two independent event sets from the surface array of…

We report a measurement of the flux of cosmic rays with unprecedented precision and statistics using the Pierre Auger Observatory. Based on fluorescence observations in coincidence with at least one surface detector we derive a spectrum for…

The origin and nature of ultrahigh-energy cosmic rays (UHECRs) are one of the most intriguing mysteries in particle astrophysics and astronomy. The two largest observatories, the Pierre Auger Observatory and the Telescope Array Experiment,…

The Pierre Auger Observatory has by now achieved an exposure of order $10^5~{\rm km}^2$ sr yr, exploring about 85% of the sky. In this talk, I will review some of the recent results, including the detailed measurements of the features in…

We consider the ultra-high energy cosmic ray (UHECR) spectrum as measured by the Pierre Auger Observatory. Top-down models for the origin of UHECRs predict an increasing photon component at energies above about $10^{19.7}$eV. Here we…

Data taken at the Pierre Auger Observatory are used to search for air showers initiated by ultra-high energy (UHE) photons. Results of searches are reported from hybrid observations where events are measured with both fluorescence and array…

Ultra-High Energy Cosmic Rays (UHECRs) are charged particles of energies above $10^{18}$ eV that originate outside of the Galaxy. Because the flux of the UHECRs at Earth is very small, the only practical way of observing UHECRs is by…

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…

Great advances have been made in the study of ultra-high energy cosmic rays (UHECR) in the past two decades. These include the discovery of the spectral cut-off near 5 x 10^19 eV and complex structure at lower energies, as well as…

The motivation, physics objectives, and technical strategy of a upgrade to the Pierre Auger Observatory are discussed.

The Pierre Auger Observatory detects ultra-high energy cosmic rays by implementing two complementary air-shower techniques. The combination of a large ground array and fluorescence detectors, known as the "hybrid" concept, means that a rich…

We present a measurement of the cosmic-ray spectrum above 100\,PeV using the part of the surface detector of the Pierre Auger Observatory that has a spacing of 750~m. An inflection of the spectrum is observed, confirming the presence of the…

The Pierre Auger Observatory (PAO) and Telescope Array (TA) collaborations report significant differences in the observed energy spectra of ultra-high-energy cosmic rays (UHECRs) above 30~EeV. In this work we present a joint fit of TA and…

In this contribution we summarize the highlights from the Pierre Auger Observatory presented at the 35th International Cosmic Ray Conference. We discuss the update of the measurement of the energy spectrum of cosmic rays over a wide range…

The southern Pierre Auger Observatory, presently under construction in Malarg"ue, Argentina, is nearing completion. The instrument is designed to measure extensive air-showers with energies ranging from $10^{18}$-$10^{20}$ eV and beyond. It…

This paper summarizes some highlights from the Pierre Auger Observatory that were presented at the ICRC 2011 in Beijing. The cumulative exposure has grown by more than 60% since the previous ICRC to above 21000 km^2 sr yr. Besides giving…

The Pierre Auger Observatory has driven the field of ultra-high-energy cosmic ray (UHECR) physics, producing several groundbreaking observations over the last 20 years. One of the most striking findings has been the complex evolution of…