Radio detection of extensive air showers at the Pierre Auger Observatory

Deployed at the end of 2010 at the Pierre Auger Observatory, the first stage of the Auger Engineering Radio Array, AERA24, consists of 24 radio stations covering an area of 0.5 km2. AERA measures the radio emission from cosmic-ray induced air showers. The amplitude of this radio emission is used to constrain the characteristics of the primary particle: arrival direction, energy and nature. These studies are possible thanks to an instrumentation development allowing self-triggered and externally triggered measurements in the MHz domain and an improved understanding of radio emission processes. In May 2013, 100 new stations were installed to cover an area of ≃6 km2, for a total of 124 stations. This stage 2 will provide higher statistics and will enhance both the estimate of the nature of the primary cosmic ray and the energy resolution above 1017 eV as an addition to detectors such as the Auger fluorescence telescopes and particle detectors. We will present the main results obtained with the stage 1 of AERA and the current status of the experiment. We will end with a brief overview of the GHz-experiments installed at the Pierre Auger Observatory.