Speaker
Description
An update of the measurement of large-scale anisotropies in the arrival directions of ultra high-energy cosmic rays detected at the Pierre Auger Observatory is presented. The established dipolar anisotropy in right ascension has now reached a significance of 6.8$\sigma$ when considering all energies above 8 EeV and 5.7$\sigma$ when only considering energies between 8 and 16 EeV. The 3D dipole amplitude and direction are reconstructed in four different energy bins above 4 EeV. In the inclusive bin above 8 EeV it points $\sim 115^\circ$ away from the Galactic centre, providing evidence for its extragalactic origin. An analysis allowing for both dipolar and quadrupolar anisotropies finds qualitatively similar dipole components and no significant quadrupole components. The results for the angular power spectrum are shown demonstrating that no other statistically significant multipoles are present. The equatorial dipole components are presented down to 0.03 EeV, using a data set obtained with a trigger that has been optimized for lower energies. We find no significant departures from isotropic expectations below 8 EeV. Finally, model predictions are discussed and compared with observations, based on source emission scenarios obtained in the combined fit of spectrum and composition above 0.6 EeV.
