Seminars and Journal Clubs
The Pierre Auger Observatory for ultra-energetic cosmic rays: status and first results
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Europe/Brussels
e.349
e.349
Description
The Pierre Auger Observatory has been designed to study with high statistics and high quality data the end of the spectrum of the cosmic rays (above 10^18 eV) using an hybrid technique: atmospheric fluorescence telescopes and a ground array of water Cherenkov detectors on the same site. It aims to solve the puzzle of their origin, which is still unknown. The results of previous experiments were controversial, especially about the observation of the so-called GZK effect (suppression of the highest energies through interaction with CMBR). Various theoretical models have been proposed to explain the observations, some of them including new physics. The southern Auger site (Malargüe, province of Mendoza, Argentina) has accumulated enough data to give some constraining results: break point in the spectrum around the GZK energy, anisotropy at highest energies, upper bounds on photon and neutrino fluxes. These results favour a standard astrophysical production (Fermi mechanism in shocks) with extragalactic sources, rather then exotic models (e.g. decay of ultra-massive objects).
The Observatory will be described and the main results will be presented and commented. Perspectives for the next future (especially the northern site in Colorado) will be discussed.