First analysis of inclined air showers detected by Tunka-Rex

¹ Institute of Applied Physics ISU, Irkutsk, Russia
² Institut für Kernphysik, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
³ Institut für Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
⁴ Skobeltsyn Institute of Nuclear Physics MSU, Moscow Russia
⁵ Institut für Experimentelle Teilchenphysik, Karlsruhe Institute of Technology (KIT), Karlsruhe Germany
⁶ Department of Physics and Astronomy, University of Delaware, Newark, DE USA

^★ now at the University of Zürich
^★★ also at Vrije Universiteit Brussel, Brussels, Belgium

Published online: 24 September 2019

Abstract

The Tunka Radio Extension (Tunka-Rex) is a digital antenna array for the detection of radio emission from cosmic-ray air showers in the frequency band of 30 to 80 MHz and for primary energies above 100 PeV. The standard analysis of Tunka-Rex includes events with zenith angle of up to 50?. This cut is determined by the efficiency of the external trigger. However, due to the air-shower footprint increasing with zenith angle and due to the more efficient generation of radio emission (the magnetic field in the Tunka valley is almost vertical), there are a number of ultra-high-energy inclined events detected by Tunka-Rex. In this work we present a first analysis of a subset of inclined events detected by Tunka-Rex. We estimate the energies of the selected events and test the efficiency of Tunka-Rex antennas for detection of inclined air showers.