Features of the Energy Spectrum of Cosmic Rays above 2.5 × 10 18     eV Using the Pierre Auger Observatory

ABREU, P.; ALLEKOTTE, I.; ALVAREZ-MUÑIZ, J.; ANCHORDOQUI, L.; ARAMO, C.; ASSIS, P.; BAKALOVA, A.; BARREIRA LUZ, R.J.; BERAT, C.; BIERMANN, P.L.; BLANCO, A.; BOHÁ?OVÁ, M.; BONNEAU ARBELETCHE, L.; BRACK, J.; BUCHHOLZ, P.; BUSCEMI, M.; CALCAGNI, L.; CARACAS, I.; CASTELLINA, A.; CAZON, L.; CHOI, K.; CLAY, R.W.; COLEMAN, A.; CONDORELLI, A.; CONVENGA, F.; DAUMILLER, K.; DE ALMEIDA, R.M.; DE MAURO, G.; DE OLIVEIRA, J.; DE VITO, E.; DELIGNY, O.; DI GIULIO, C.; DOBRIGKEIT, C.; DOS ANJOS, R.C.; ENGEL, R.; ESCOBAR, C.O.; FARMER, J.; FAZZINI, N.; FICK, B.; FODRAN, T.; FUSTER, A.; GARCÍA, B.; GESUALDI, F.; GIACCARI, U.; GLOMBITZA, J.; GOLUP, G.; GONGORA, J.P.; GÓRA, D.; GRUBB, T.D.; GUIDO, E.; HAMPEL, M.R.; HARVEY, V.M.; HECK, D.; HÖRANDEL, J.R.; HUEGE, T.; ISAR, P.G.; KÄÄPÄ, A.; KEMP, J.; KLEINFELLER, J.; LAGO, B.L.; LEIGUI DE OLIVEIRA, M.A.; LHENRY-YVON, I.; LÓPEZ, R.; LUCERO, A.; MANCARELLA, G.; MANSHANDEN, J.; MARIAZZI, A.G.; MARTELLO, D.; MASTRODICASA, M.; MATTHIAE, G.; MEDINA-TANCO, G.; MERENDA, K.-D.; MIRAMONTI, L.

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2020 p. 121106 - 121106

0031-9007

We report a measurement of the energy spectrum of cosmic rays above 2.5×10^18  eV based on 215 030 events. New results are presented: at about 1.3×10^19  eV, the spectral index changes from 2.51±0.03(stat)±0.05(syst) to 3.05±0.05(stat)±0.10(syst), evolving to 5.1±0.3(stat)±0.1(syst) beyond 5×10^19  eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5×10^18  eV is [5.66±0.03(stat)±1.40(syst)]×10^53  erg Mpc^−3.