Radio detection of cosmic ray air showers by the RAuger experiment, a fully autonomous and self-triggered system installed at the Pierre Auger Observatory

Abstract

RAuger is a radio experiment constituting three fully autonomous and self-triggered radio stations installed at the center of the Pierre Auger Observatory's Surface Detector (SD). It aims at the radio detection of the electric field emitted by the secondary charged particles of the atmospherical shower initiated by ultra-high energy cosmic rays. Installed in November 2006, we recorded the first atmospherical showers in coincidence with the SD in July 2007. Up to now, 65 such coincidences have been obtained. The skymap in local coordinates (zenith angle, azimuth) of these events presents a strong azimuthal asymmetry in agreement with what was observed in the Northern hemisphere by the CODALEMA experiment (the asymmetry is simply switched by 180° in azimuth). We also recorded a threefold coincidence making possible a complete reconstruction: both the radio reconstructed shower axis and the shower energy are in perfect agreement with the SD estimations.