Pierre Auger Observatory

Hybrid Detector

Auger cosmic ray shower 265x65

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

Time Lapse Video

Who Was Pierre Auger?

pierre auger 1935 265x65

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

»Oh-my-God«-partiklen – July 28, 2017


Are you interested in brushing up your Danish?
Science journalist Gunver Lystbæk Vestergård wrote a feature article on the Pierre Auger Observatory that appeared in the Danish weekly newspaper Weekendavisen – the second largest in Denmark.

Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

Cosmic rays are mostly charged particles that  reach Earth from outer space. Although they were discovered more than a century ago, the origin of the ultra-high energy ones (with an energy above 1018 eV, or 100,000 times more energetic than the particles in the LHC beam, the most powerful particle accelerator on Earth) is still a puzzle. The large area of the Pierre Auger Observatory of about 3000 km2 compensates for the low flux of such particles and allows us to search for an excess/deficit of events arriving from different directions in the celestial sphere.


Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory

The Pierre Auger Collaboration has investigated the constraining power of the cosmic ray spectrum and composition measurements with respect to the properties of the possible sources.


Search for photons above 10^18 eV with the hybrid detector of the Pierre Auger Observatory

The Pierre Auger Collaboration has searched for the possible presence of photons with energies exceeding 1018 eV in the flux of cosmic rays arriving at Earth. These ultra-high energy photons are produced in interactions of the charged cosmic rays with energies close to 1020 eV with the cosmic microwave background (GZK effect).


Impact of atmospheric effects on the energy reconstruction of air showers observed by the surface detectors of the Pierre Auger Observatory

When an ultrahigh-energy cosmic ray impacts the Earth’s atmosphere, it can generate an enormous cascade of billions of energetic particles capable of reaching the ground. Such a cascade is dubbed an “extensive air shower” (EAS) and is routinely being detected by the Pierre Auger Observatory in Argentina near the city of Malargüe, using an array of surface detectors deployed over 3000 km2.


Search for photon point sources at the Pierre Auger Observatory

One of the most pressing mysteries in astroparticle physics is the composition and origin of cosmic rays at energies around 1 EeV = 1018 eV. In contrast to charged particles, deflected in galactic and extragalactic magnetic fields, neutral particles such as neutrinos, neutrons, or photons point back to their production site. One way to learn more about sources of ultra-high energy cosmic rays is therefore to search for an accumulation of events from specific directions. This is akin to astronomical observations of a distant galaxy, say, made with an optical telescope collecting photons of visible light.


Page 1 of 4

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...