J. AbrahamP. AbreuM. AgliettaC. AguirreE. J. AhnD. AllardI. AllekotteJ. AllenP. AllisonJaime Álvarez-Muñiz2026-03-222026-03-22200910.1016/j.astropartphys.2009.04.003https://doi.org/10.1016/j.astropartphys.2009.04.003https://andeanlibrary.org/handle/123456789/43244Citaciones: 149enPierre Auger ObservatoryPhysicsCosmic rayAugerPhotonObservatoryUltra-high-energy cosmic rayFlux (metallurgy)Nuclear physicsAstrophysicsUpper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatoryarticle