Cosmic Ray Composition with the Pierre Auger Observatory -- Ioana Maris -- Institut fur Kernphysik/Karlsruhe

jeudi 3 déc. 2009, 14:00 → 15:00 Europe/Paris

Amphi Grossetete (LPNHE)

The estimation of the mass composition of ultra high energy cosmic rays, together with the additional information on their energy spectrum, allow to distinguish between different astrophysical scenarios of acceleration and propagation. We report on studies of the composition of cosmic rays above 1 EeV with the Pierre Auger Observatory, including a discussion of the systematic uncertainties, e.g. the dominating uncertainty from the modeling of hadronic interactions in air-shower simulations. The detection of longitudinal air shower profiles with the fluorescence detector is described and the recent high-precision measurements of the average shower maximum and its fluctuations as a function of energy are presented. Furthermore, mass sensitive parameters that can be obtained from the data recorded with the surface detector of the observatory are presented.