Ultrahigh-Energy Cosmic Ray Composition from the Distribution of Arrival Directions

Understand

The sources of ultrahigh-energy cosmic rays (UHECRs) have been difficult to catch.

• It was recently pointed out that while sources of UHECR protons exhibit anisotropy patterns that become denser and compressed with rising energy, nucleus-emitting-sources give rise to a cepa stratis (onion-like) structure with layers that become more distant from the source position with rising energy.
• The peculiar shape of the hot spots from nucleus-accelerators is steered by the competition between energy loss during propagation and deflection on the Galactic magnetic field (GMF).
• Here, we run a full-blown simulation study to accurately characterize the deflections of UHECR nuclei in the GMF.