Pierre Auger collaboration (509 authors)Abreu, P.Andringa, S.Assis, P.Brogueira, P.Cazon, L.Conceicao, R.Diogo, F.Espadanal, J.Goncalves, P.Pimenta, M.Santo, C.E.Santos, E.Tome, B.2019-02-032019-02-032012-10http://dx.doi.org/10.1088/0004-637X/760/2/148http://hdl.handle.net/10400.26/26295A 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.engjournal article2019-02-03