Observation of radio signals from air showers at the Pierre Auger Observatory

Abstract

Radio detection of cosmic ray induced air showers has been demonstrated in dedicated setups in the past. Currently, radio detector setups are being tested at the Pierre Auger Observatory, in Malargüe, Argentina, for the detection of ultra high energy cosmic rays. These efforts have been rewarded with promising results. Radio signals from air showers have been measured in coincidence with the Auger surface detector array. One of the current data sets consists of 313 triggered radio events in coincidence with the surface detector of the observatory. These events have been used to make first analyses, which focus on the lateral distribution function of the radio signals and on the reconstruction of the arrival direction of cosmic rays. Furthermore, the radio background data have been studied. A periodic variation corresponding to the apparent motion of the galactic center has been observed. New, stand-alone, radio detectors have been developed and the next phase of testing at the Auger Observatory has started in May 2008. The aim is to show that an independent radio detector at the Auger Observatory with an area of about 20 km 2 is feasible.