Speaker
Description
The origin of cosmic rays remains an unresolved fundamental problem in astrophysics. The synergy of multiple observational probes, including the energy spectra, the mass composition, and anisotropy is a viable way to jointly uncover this mystery. In this work, we propose that the energy-dependence of those observables in a wide energy range, from $O(10)$ GeV to ultrahigh energies of $10^{11}$ GeV, share quite a few correlated features, indicating a strong co-evolution which could be a consequence of the underlying origin of different source populations. We model these structures with a four-component model, i.e., the ensemble of Galactic sources, a local source close to the solar system, and the ensemble of two extra-galactic source populations. In this scenario, the 10 TeV bump is due to the contribution of the local source, the knee is due to the maximum acceleration energy of protons by the Galactic source population, the second knee is due to the maximum acceleration energy of iron nuclei by Galactic sources, the dip feature between the two knees is due to the emergence of the extra-galactic component, the ankle comes from the transition from one extragalactic component to the other, and the spectral suppression at the highest energies comes from either the acceleration limit or the photo-disintegration of the second extragalactic component.
