Measurement of the UHECR spectrum above 1019 eV at the Pierre Auger Observatory using showers with zenith angles greater than 60°

PIERRE AUGER COLLABORATION (J. ABRAHAM, ... , A. MARIAZZI, ET AL)

Merida, Mejico

Conferencia; 30th International Cosmic Ray Conference; 2007

We report on the cosmic ray spectrum obtained using the inclined events detected withthe Pierre Auger Observatory. Showers with zenith angles between 60$^\circ$ and80$^\circ$ recorded in the period between January 1st, 2004 and December 31st, 2006are analysed. Showers are first reconstructed in arrival direction and then fitted todensity maps of the muon numbers obtained from $10^{19}$eV simulated proton showersfor different arrival directions, toobtain the core position and an overall normalisation factor $N_{19}$ which is usedas an energy estimator. The parameter $N_{19}$ is shown to be correlated with theshower energy measured with the fluorescence technique for a sub-sample of goodquality hybrid showers. The correlation obtained between $N_{19}$ and energy is usedto measure the energy of all the showers.