Measurement of the cosmic ray energy spectrum using hybrid events of the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

European Physical Journal Plus

Springer

Año: 2012 vol. 127 p. 87 - 102

2190-5444

The energy spectrum of ultra-high energy cosmic rays above 1018 eV is measured using thehybrid events collected by the Pierre Auger Observatory between November 2005 and September 2010.The large exposure of the Observatory allows the measurement of the main features of the energy spectrumwith high statistics. Full Monte Carlo simulations of the extensive air showers (based on the CORSIKAcode) and of the hybrid detector response are adopted here as an independent cross check of the standardanalysis (Phys. Lett. B 685, 239 (2010)). The dependence on mass composition and other systematicuncertainties are discussed in detail and, in the full Monte Carlo approach, a region of confidence for fluxmeasurements is defined when all the uncertainties are taken into account. An update is also reported ofthe energy spectrum obtained by combining the hybrid spectrum and that measured using the surfacedetector array.