A Search for Point Sources of EeV Neutrons

TL;DR

This study conducted a comprehensive sky survey using the Pierre Auger Observatory to detect EeV neutrons from point sources, but found no significant signals, thereby constraining models of galactic ultra-high energy cosmic ray origins.

Contribution

It presents the most sensitive search to date for EeV neutrons from point sources, setting upper limits on their flux across the sky.

Findings

No statistically significant excess of EeV neutrons detected.

Upper limits established on neutron flux from various directions.

Results constrain galactic cosmic ray production scenarios.

Abstract

A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from -90 to +15 degrees in declination using four different energy ranges above 1 EeV (10^18 eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultra-high energy cosmic rays in the Galaxy.