Relatore
Summary
The Pierre Auger Cosmic-Ray Observatory uses the earth's atmosphere as a calorimeter
to measure extensive air-showers created by particles of astrophysical origin. Some
of these particles carry joules of energy. At these extreme energies, test beams are
not available in the conventional sense. Yet understanding the energy response of the
observatory is important because the distance the highest energy cosmic-rays
propagate through the cosmic microwave background radiation is predicted to be strong
function of energy. This talk will discuss recently reported results from the
observatory and the use of calibrated laser "test-beams" that simulate the optical
signatures of ultra-high energy cosmic rays. The status of the much larger (200,000
km^3) companion detector planned for the northern hemisphere will also be outlined.
