Pierre Auger Observatory

Hybrid Detector

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The hybrid nature of the Pierre Auger Observatory provides for two independent ways to see cosmic rays. Read More...

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Who Was Pierre Auger?

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The Pierre Auger Observatory experiment was named after Pierre Victor Auger (1899 - 1993) Read More...

A Search for Ultrahigh-Energy Neutrinos in Auger data in Coincidence with Gravitational Waves

100 years after their prediction by Albert Einstein, Gravitational Waves (GW) were detected in 2015 by the LIGO detectors. With the surface detector of Auger we have searched for ultrahigh-energy neutrinos in temporal and spatial coincidence with such remarkable events.


Cosmic-Ray Showers Reveal Muon Mystery

The Pierre Auger Observatory has detected more muons from cosmic-ray showers than predicted by the most up-to-date particle-physics models.
By T. Gaisser Physics 9, 125 (2016)


Evidence for a mixed mass composition at the 'ankle' in the cosmic ray spectrum

The highest energy cosmic rays remain elusive and mysterious, and their study requires extraordinary efforts. At the Pierre Auger Observatory in Argentina, the giant air showers of particles created by these cosmic rays are detected when they slam into the ground by a large array of water tanks equipped with electronic detectors. But on dark nights they are simultaneously detected by telescopes sensitive to the faint sky glow left by the air showers. The new report by the Pierre Auger Collaboration correlates in detail the signals in the water tanks with those from the telescopes. The correlation is uniquely sensitive to the presence in the primary beam of nuclei with different masses, and is used in particular to help resolve how many types of atomic nuclei contribute to the cosmic ray flux.


A world-record sensitivity on the flux of ultrarelativistic magnetic monopoles

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Maxwell’s unified description of electric and magnetic phenomena is one of the greatest achievements of 19th century physics. Free magnetic charges and currents are not allowed in Maxwell’s equations, a consequence of their apparent absence in Nature. However, their existence would naturally explain the quantization of electric charge, as first noted by Dirac in 1931.


Reconstruction of the muon production depth in the atmosphere with the surface detectors of the Pierre Auger Observatory

Cosmic rays are energetic particles, mostly atomic nuclei, raining down upon the Earth from the depths of the cosmos. Understanding their detailed nature and origins remains a primary goal in modern-day astroparticle physics.


Obituary on Jim Cronin by Alan Watson

2016-09-22 Cronin On 21 September 2016 Alan Watson published an obituary on his collegue and friend Jim Cronin on the website of the international weekly journal of science Nature.


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Auger On Site

Shower Simulations

shower simulation

A computer is used to construct a model of what happens in a high energy cosmic ray airshower. Read More...

Google Earth


A model of the Observatory layout was constructed, to be viewed interactively using Google Earth. Read More...

Event Display


The Pierre Auger Collaboration agreed on making 1% of its data available to the public. Read More...