Measurement of the cosmic ray spectrum above 4 × 1018 eV using inclined events detected with the Pierre Auger Observatory

AAB, A.; ABREU, P.; AGLIETTA, M.; AHN, E.J.; AL SAMARAI, I.; ALBUQUERQUE, I.F.M.; ALLEKOTTE, I.; ALLISON, P.; ALMELA, A.; ALVAREZ CASTILLO, J.; ALVAREZ-MUÑIZ, J.; ALVES BATISTA, R.; AMBROSIO, M.; AMINAEI, A.; ANCHORDOQUI, L.; ANDRINGA, S.; ARAMO, C.; ARANDA, V.M.; ARQUEROS, F.; ARSENE, N.; ASOREY, H.; ASSIS, P.; AUBLIN, J.; AVE, M.; AVENIER, M.; AVILA, G.; AWAL, N.; BADESCU, A.M.; BARBER, K.B.; BÄUML, J.; BAUS, C.; BEATTY, J.J.; BECKER, K.H.; BELLIDO, J.A.; BERAT, C.; BERTAINA, M.E.; BERTOU, X.; BIERMANN, P.L.; BILLOIR, P.; BLAESS, S.G.; BLANCO, A.; BLANCO, M.; BLEVE, C.; BLÜMER, H.; BOHÁ?OVÁ, M.; BONCIOLI, D.; BONIFAZI, C.; BORODAI, N.; BRACK, J.; BRANCUS, I.; BRIDGEMAN, A.; BROGUEIRA, P.; BROWN, W.C.; BUCHHOLZ, P.; BUENO, A.; BUITINK, S.; BUSCEMI, M.; CABALLERO-MORA, K.S.; CACCIANIGA, B.; CACCIANIGA, L.; CANDUSSO, M.; CARAMETE, L.; CARUSO, R.; CASTELLINA, A.; CATALDI, G.; CAZON, L.; CESTER, R.; CHAVEZ, A.G.; CHIAVASSA, A.; CHINELLATO, J.A.; CHUDOBA, J.; CILMO, M.; CLAY, R.W.; COCCIOLO, G.; COLALILLO, R.; CO

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

IOP PUBLISHING LTD

Año: 2015 vol. 2015

1475-7516

A measurement of the cosmic-ray spectrum for energies exceeding 4×1018 eV is presented, which is based on the analysis of showers with zenith angles greater than 60° detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×1018 eV, the "ankle", the flux can be described by a power law E-γ with index γ=2.70 ± 0.02 (stat) ± 0.1 (sys) followed by a smooth suppression region. For the energy (Es) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12 ± 0.25 (stat)+1.0-1.2 (sys))×1019 eV.