Hybrid performance of the Pierre auger observatory

Abstract

A key feature of the Pierre Auger Observatory is its hybrid design, in which ultra high energy cosmic rays are detected simultaneously by fluorescence telescopes and a ground array. The two techniques see air showers in complementary ways, providing important cross-checks and measurement redundancy. Much of the hybrid capability stems from the accurate geometrical reconstruction it achieves, with accuracy better than either the ground array detectors or a single telescope could achieve independently. We have studied the geometrical and longitudinal profile reconstructions of hybrid events. We present the results for the hybrid performance of the Observatory, including trigger efficiency, energy and angular resolution, and the efficiency of the event selection.