April 4, 2008 (Friday) Maxim Pospelov, Victoria University
April 7, 2008 (Monday) Andrea Pocar, Stanford
April 28, 2008 (Monday) Miguel Mostafa, University of Utah
May 12, 2008 (Monday) Weiming Yao, LBNL
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
Since the first detection of a cosmic ray event with energy above 10 20 eV in 1962, their nature and origin remain unknown. At these energies, it is expected that the cosmic ray flux undergo a strong suppression. Due to the extreme rarity of these ultra high energy cosmic rays, they must be observed indirectly through the observation of extensive air showers, and the lack of knowledge of hadronic interactions at these energies leads to inherent difficulties in characterising the properties of the primary particle. A new generation cosmic ray detector, the Pierre Auger Observatory, has been designed to study cosmic rays with energy above 10 18 eV and answer the crucial questions of ultra high energy cosmic ray physics. The Southern Observatory in Argentina has been collecting data since 2004 and, although still under construction, its exposure is already larger than that of any previous experiment. After three years of operation, we found strong indications that ultra high energy cosmic rays come from nearby, extragalactic sources, opening a window for charged particle astronomy. In this colloquium, I will describe the Pierre Auger Observatory in its astrophysical context, our most recent results, and the exciting prospects for the near future.
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45