Scientists celebrate inauguration of Pierre Auger Observatory
Nov. 10, 2008
For immediate release
Rosa Pacheco, Pierre Auger Observatory,
phone: +54 2627 471 562
Auger country representatives:
Scientists of the Pierre Auger Observatory, a project to study the highest-energy cosmic rays,
will celebrate the inauguration of the southern site of their observatory in Malargüe,
Argentina, this Friday, November 14, 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.
The inauguration celebration in Argentina will begin with an informal reception on 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.
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
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 Pierre Auger collaboration includes more than 370 scientists and engineers from
60 institutions in
More than 40 funding agencies
are contributing to the Pierre Auger Observatory.