Media invited to attend Pierre Auger Observatory Inauguration, November 14-15, 2008, in Malargüe, Argentina

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Scientists of the Pierre Auger Observatory, a project to study the highest-energy cosmic rays, will celebrate the inauguration of their southern site in Malargüe, Argentina, on November 14 and November 15, 2008. The event will mark the completion of the first phase of the Observatory construction and the beginning of the project’s second phase, which includes plans for a northern hemisphere site in Colorado, USA, and enhancements to the southern hemisphere site.

Media representatives wishing to attend should make arrangements as soon as possible. Please register at

The Pierre Auger Observatory is exploring the mysteries of the highest-energy cosmic rays – charged particles showering the Earth at energies 10 million times higher than the world’s highest-energy particle accelerator. Until now, there has been no consensus on the origin of these highest-energy cosmic rays.

To witness these extremely rare events, the Pierre Auger Collaboration began the construction of its Southern Observatory in the year 2000. The project consists of an array of 1600 detectors spread over 3000 square kilometers in Argentina’s Mendoza Province, just east of the Andes Mountains. Surrounding the array is a set of 24 fluorescence telescopes that view the faint ultraviolet light emitted by the cosmic-ray shower particles as they cascade through the atmosphere. The collaboration includes more than 350 physicists from 70 institutions in 17 countries, which have shared the construction cost of approximately $53 million.

The Pierre Auger collaboration published its first physics results in the fall of 2007, revealing new insights into the properties of the highest-energy particles in the universe. The collaboration found that the arrival directions of the highest-energy cosmic rays are anisotropic. The arrival directions correlate with nearby galaxies that contain actively radiating black holes. Several science organizations selected this remarkable result as one of the most important scientific breakthroughs in 2007.

The collaboration used its growing detector array to measure the cosmic-ray energy spectrum at the highest energies, achieving higher precision than any previous experiment. The Auger scientists found a fall-off of the flux at the highest energies. This is consistent with an idea, proposed about 40 years ago, that cosmic rays interact with photons of the ubiquitous microwave background radiation on their way through the universe. New limits on the photon and neutrino content in cosmic rays have put stringent limits on theories of cosmic-ray origins.

The Inauguration Celebration in Argentina will begin with an informal reception the evening of Thursday, November 13. A symposium on Friday, November 14, will include presentations on the origins of the project, the construction of the experiment and the latest science results. Guided tours of the observatory will be offered on Saturday, November 15. Those who would like to stay an extra day may attend the local Malargüe Day festivities on November 16. Although the Auger site is in a rather remote location, the experience of seeing this unique project, attending its inauguration, and exploring the area, will be well worth the long journey.

In November, the southern hemisphere is in its spring season. The city of Malargüe is a popular destination for hiking, horseback riding, white-water rafting, and fly fishing, and is close to some of the finest wine-growing regions in Argentina. Excursions to these outdoor activities and other local places of interest will be available before and after the ceremonies.

Auger country representatives: