Speaker
Description
The detection of astrophysical photons of the highest energies is an important goal of modern gamma-ray astronomy and will improve our understanding of sources of cosmic ray acceleration in our Galaxy. While current generation gamma-ray observatories have barely reached the PeV energy range, higher energies still remain elusive, as they require large areas and efficient gamma-hadron separation. Furthermore, ultra-high energy (UHE) gamma rays were so far only detected using optical or particle detectors while radio detection of UHE photons is still missing. This might change with the SKA-Low observatory which is currently under construction.
The SKA-Low detector will be the most dense radio antenna array in the world, encompassing approximately 60000 broadband antennas (50 – 350 MHz) in its dense core. Currently, the energy threshold for radio detection of extensive air showers lies in the tens of PeV range for the signal to be visible in single antennas. However, this threshold can be lowered to a few PeV by exploiting SKA-Low's unprecedented antenna density using near-field beamforming. This contribution presents results that point to the possibility of a first detection of UHE gamma rays with radio and discusses the associated challenges.