Radio detection of high-energy cosmic rays with the Auger Engineering Radio Array (PISA 2015)

TL;DR

The paper discusses the development and initial physics results of AERA, the world's largest radio antenna array for cosmic-ray detection, which enhances the Pierre Auger Observatory to study high-energy cosmic rays with improved calibration and cross-validation techniques.

Contribution

This work introduces AERA as a large-scale autonomous radio array for cosmic-ray detection, demonstrating technical feasibility and initial physics capabilities at unprecedented energies.

Findings

AERA successfully demonstrates large-scale autonomous antenna operation.

Calibration techniques for antennas and timing are developed and validated.

Initial measurements show competitive accuracy in determining air shower direction and energy.

Abstract

The Auger Engineering Radio Array (AERA) is an enhancement of the Pierre Auger Observatory in Argentina. Covering about View the $17\,$km$^2$, AERA is the world-largest antenna array for cosmic-ray observation. It consists of more than 150 antenna stations detecting the radio signal emitted by air showers, i.e., cascades of secondary particles caused by primary cosmic rays hitting the atmosphere. At the beginning, technical goals had been in focus: first of all, the successful demonstration that a large-scale antenna array consisting of autonomous stations is feasible. Moreover, techniques for calibration of the antennas and time calibration of the array have been developed, as well as special software for the data analysis. Meanwhile physics goals come into focus. At the Pierre Auger Observatory air showers are simultaneously detected by several detector systems, in particular water-Cherenkov detectors at the surface, underground muon detectors, and fluorescence telescopes, which enables cross-calibration of different detection techniques. For the direction and energy of air showers, the precision achieved by AERA is already competitive; for the type of primary particle, several methods are tested and optimized. By combining AERA with the particle detectors we aim for a better understanding of cosmic rays in the energy range from approximately $0.3$ to $10\,$EeV, i.e., significantly higher energies than preceding radio arrays.