X_max reconstruction for cosmic-ray air showers detected with 3 elevated radio antennas at IceCube

IceTop is the surface array of the IceCube Neutrino Observatory used for the detection of cosmic-ray air showers in the energy range of 1 PeV - 1 EeV. An enhancement of the surface array with scintillator detectors and elevated radio antennas has been designed to improve the capabilities for cosmic-ray and air-shower physics of the Observatory. A prototype station consisting of 8 scintillators and 3 radio antennas has been deployed to the South Pole and has been taking data for several years. One of the goals of the radio antennas in particular is the reconstruction of the depth of shower maximum, X_max, an observable sensitive to the mass of cosmic-ray nuclei.

The state-of-the art method for reconstructing X_max with surface arrays of radio antennas consists out of a direct comparison of a library of simulated air showers to individual recorded events. By minimizing the difference between different radio observables obtained in each antenna compared to the simulated events, a reconstruction of both the primary energy and Xmax is obtained. In this work, this method is applied to data recorded with the three antennas of the prototype station, showing the potential for Xmax reconstruction in the frequency band of 80 to 300 MHz.