Treasure Maps for Detections of Extreme Energy Cosmic Rays

Understand

The origin of Ultra High Energy Cosmic Rays is a 60-year old mystery.

• We show that with more events at the highest energies (above 150~EeV) it may be possible to limit the character of the sources and learn about the intervening magnetic fields.
• Individual sources become more prominent, relative to the background, as the horizon diminishes.
• An event-by-event, composition-dependent observatory would allow a ``tomography'' of the sources as different mass and energy groups probe different GZK horizons.