Measurement of the energy spectrum of cosmic rays above 1018 eV using the Pierre Auger Observatory

ABRAHAM, JORGE ET AL.; ABREU, P.; AGLIETA, M; GARCIA, B (400 AUTORES ORDEN ALFABETICO)

PHYSICS LETTERS B

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2010 vol. 685 p. 239 - 246

0370-2693

We report a measurement of the flux of cosmic rays with unprecedented Precision and statistics using the Pierre Auger Observatory. Based on fluorescence observations in coincidence with at least one surfacedetector we derive a spectrum for energies above 1018 eV. We also update the previously published energy spectrum obtained with the surface detector array. The two spectra are combined addressing the systematic uncertainties and, in particular, the influence of the energy resolution on the spectral shape.The spectrum can be described by a broken power law E −γ with index γ = 3.3 below the ankle whichis measured at log10 ( E ankle /eV) = 18.6. Above the ankle the spectrum is described by a power law withindex 2.6 followed by a flux suppression, above about log10 ( E /eV) = 19.5, detected with high statisticalsignificance.