Cosmic ray physics with the Auger Engineering Radio Array (AERA)

Abstract

The Auger Engineering Radio Array consists of 153 autonomous radio stations at the site of the Pierre Auger Observatory in Malargüe, Province of Mendoza, Argentina. Covering an area of 17 km2, AERA is the largest radio detector worldwide for ultra-high energy cosmic ray (UHECR) physics. The radio stations are sensitive in the 30 to 80 MHz band and measure the coherent radio signal emitted by the electromagnetic air shower component.Steady progress in radio detection techniques and a very good understanding of the radio emission mechanism made AERA a capable tool for cosmic ray physics: We use AERA radio data to reconstruct the arrival direction and the energy of the air shower with a precision competitive with standard reconstruction techniques. Even the determination of the absolute energy scale seems possible. The primary mass composition is determined from the distribution of the shower maximum, which is currently measured with a precision of 40 g/cm2 by the radio method. Furthermore, since radio measurements are purely sensitive to the electromagnetic component of the air shower, they can be combined with measurements of particle detectors for an additional way to estimate the mass of the primary particle by means of the electron-to-muon ratio.This contribution reviews the recent analysis methods for radio signals and shows some results for the determination of air shower properties gained with AERA.