A nearby source of ultra-high energy cosmic rays

Understand

Recently the Telescope Array collaboration reported an observation of cosmic ray event with very high energy 244 EeV ($2.44 \times 10^{20}$ eV).

• Importantly, the event is hard to correlate with the matter distribution in the local Universe, even after taking into account deflections in magnetic fields.
• This implies that the event is likely a nucleus with a large charge.
• An attenuation length of the nucleus of such a high energy in intergalactic space is quite small, therefore its source should be relatively close to our Galaxy.