A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory

J. ABRAHAM,...; X. BERTOU

ASTROPARTICLE PHYSICS

ELSEVIER SCIENCE BV

Año: 2010 vol. 33 p. 108 - 129

0927-6505

The air fluorescence detector of the Pierre Auger Observatory is designed to perform calorimetric mea- surements of extensive air showers created by cosmic rays of above 1018 eV. To correct these measure- ments for the effects introduced by atmospheric fluctuations, the Observatory contains a group of monitoring instruments to record atmospheric conditions across the detector site, an area exceeding 3000 km2. The atmospheric data are used extensively in the reconstruction of air showers, and are par- ticularly important for the correct determination of shower energies and the depths of shower maxima. This paper contains a summary of the molecular and aerosol conditions measured at the Pierre Auger Observatory since the start of regular operations in 2004, and includes a discussion of the impact of these measurements on air shower reconstructions. Between 1018 and 1020 eV, the systematic uncertainties due to all atmospheric effects increase from 4% to 8% in measurements of shower energy, and 4 g cm􏰕2 to 8 g cm􏰕2 in measurements of the shower maximum.