A Targeted Search for Point Sources of EeV Neutrons

Understand

A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source.

• To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine "target sets", in addition to the search for a neutron flux from the Galactic Center or from the Galactic Plane.
• Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay.
• These searches do not find evidence for a neutron flux from any class of candidate sources.