Related papers: Composition Studies with the Pierre Auger Observat…
The mass composition of ultra-high-energy cosmic rays is an open problem in astroparticle physics. It is usually inferred from the depth of the shower maximum (Xmax) of cosmic-ray showers, which is only ambiguously determined by modern…
The aim of the Pierre Auger Observatory is the investigation of the nature of cosmic ray particles at ultra-high energies. It can simultaneously observe the longitudinal air shower development in the atmosphere as well as particle densities…
The Southern Pierre Auger Observatory is now nearing completion and the accumulating data sample has already allowed to extract scientific results of relevance for ultra-high energy cosmic-ray (UHECR) physics. This lecture focuses on the…
The development of an extensive air shower depends not only on the nature of the primary ultra-high-energy cosmic ray but also on the properties of the hadronic interactions. For energies above those achievable in human-made accelerators,…
The Pierre Auger Observatory is a major international effort aiming at high-statistics study of highest energy cosmic rays. A general description of the experimental set-up and overall performance of the detector at first light are…
The observation of photons with energies above 10^18 eV would open a new window in cosmic-ray research, with possible impact on astrophysics, particle physics, cosmology and fundamental physics. Current and planned air shower experiments,…
Studies of the cosmic ray energy spectrum at the highest energies with the Pierre Auger Observatory
In its Phase I, the Pierre Auger Observatory has led to several observations, driving the field of ultra-high-energy cosmic ray (UHECR) research over the last 20 years. Major achievements obtained so far include the unprecedented precise…
Fluorescence detectors of the Pierre Auger Observatory have been operating in a stable manner since January 2004. After a brief review of the physical characteristics of the detectors, the associated atmospheric monitoring, the calibration…
Air-showers measured by the Pierre Auger Observatory were analyzed in order to extract the depth of maximum (Xmax).The results allow the analysis of the Xmax distributions as a function of energy ($> 10^{17.8}$ eV). The Xmax distributions,…
The air fluorescence detectors (FDs) of the Pierre Auger Observatory are vital for the determination of the air shower energy scale. To compensate for variations in atmospheric conditions that affect the energy measurement, the Observatory…
The world's largest cosmic-ray detector is nearing completion in the remote Pampas of Argentina. This instrument measures extensive air-showers with energies from ${10^{18}-10^{20}}$ eV and beyond. A surface detector array of area 3000…
The Pierre Auger Observatory in Malarg\"ue, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 1018 eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly…
A key feature of the Pierre Auger Observatory is its hybrid design, in which ultra high energy cosmic rays are detected simultaneously by fluorescence telescopes and a ground array. The two techniques see air showers in complementary ways,…
A wide range of atmospheric monitoring instruments is employed at the Pierre Auger Observatory: two laser facilities, elastic lidar stations, aerosol phase function monitors, a horizontal attenuation monitor, star monitors, weather…
The Auger project 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 and is now completed. Results on…
The Pierre Auger Observatory is the most sensitive instrument to detect photons with energies above $10^{17}$ eV. It measures extensive air showers generated by ultra high energy cosmic rays using a hybrid technique that exploits the…
We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger…
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…
The scientific achievements of the Pierre Auger Collaboration cover diverse and complementary fields of research. The search for the origin of ultra-high energy cosmic rays (UHECRs) is based on the measurement of the energy spectrum and…