Measuring the depth of shower maximum with SKA1-low: a first simulation study

As LOFAR has already demonstrated, using a dense array of radio antennas for detecting extensive air showers initiated by cosmic rays in the Earth's atmosphere makes it possible to measure the depth of shower maximum for individual showers with a statistical uncertainty of less than 20 g/cm². This allows detailed studies of the mass composition in the energy region around 10¹⁷ eV where the transition from a galactic to an extragalactic origin could occur. As of 2023, the Square Kilometre Array will constitute the world's largest telescope in radio astronomy. Since SKA1-low, the low frequency part, ideally suited to detect extensive air showers initiated by cosmic ray via radio emission, will provide a much denser and very homogeneous antenna array with roughly 70,000 antenna on an area of about 0.5 km² and a large bandwidth of 50-350 MHz it is expected to reach an even smaller uncertainty on the shower-maximum reconstruction. We present results of a first simulation study with focus on the potential to reconstruct the depth of shower maximum for individual showers measured with SKA1-low, showing that a mean reconstruction uncertainty of less than 10 g/cm² seems to be achievable.