Author: Haris LyberisPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
This thesis concerns the study anisotropies of UHECRs observed by the Pierre Auger Observatory. R&D was done to increase of the dynamical range of Hamamatsu PMTs using the technique based on the reading out of deeper dynodes, reaching 20 bits. To increase the statistics at high energy, a relax trigger selection was designed to be used in further Auger data analysis. Further, point sources were searched in direction of the Galactic Center and Centaurus A. We also developed a new method for searching for anisotropies without relying on any catalog that provides the clustering scale and an analytical way to compute the chance probability. Using it, we place important limits on the density of sources and the deflections of the extra-galactic cosmic rays. In the low energy range, we performed a first harmonic analysis using a new method to account for detector effects. Upper bounds were given above 1 EeV with an indication of a signal at all energies pointed out by the smooth transition of the phase. Finally, using both a numerical method to solve the diffusion equation in a simplified galactic magnetic field mo-del and Monte Carlo simulations, we compare the resulting anisotropy with the possible one, studying also relaxing some hypothesis (stationary sources, isotropic emission).