The sources of ultra-high energy cosmic rays are not yet known .
However , the discovery of anisotropic cosmic rays above 57 \times 10 ^ { 18 } eV by the Pierre Auger Observatory suggests that a direct source detection may soon be possible .
The near-future prospects for such a measurement are heavily dependent on the flux of the brightest source .
In this work , we show that the flux of the brightest source above 57 \times 10 ^ { 18 } eV is expected to comprise 10 % or more of the total flux if two general conditions are true .
The conditions are : 1 . )
the source objects are associated with galaxies other than the Milky Way and its closest neighbors , and 2 . )
the cosmic ray particles are protons or heavy nuclei such as iron and the Greisen-Zatsepin-Kuz ’ min effect is occurring .
The Pierre Auger Observatory collects approximately 23 events above 57 \times 10 ^ { 18 } eV per year .
Therefore , it is plausible that , over the course of several years , tens of cosmic rays from a single source will be detected .