Speaker
Description
Measuring radio signals from cosmic-ray air showers has enabled detailed air shower reconstructions and cosmic-ray mass composition analyses with LOFAR.
LOFAR is already a dense array for air-shower standards; with nearly 60,000 antennas in a 1 km diameter, the low-frequency part of SKA in Australia will increase this density by two orders of magnitude.
As we show from a detailed simulation study, this allows to reconstruct the longitudinal evolution of the number of particles in the shower, rather than just its maximum. This level of detail for individual showers has not yet been possible in cosmic-ray observatories.
We discuss the new possibilities for cosmic-ray measurements, which include additional independent information on the mass composition between $10^{16}$ and $10^{18}$ eV, in particular the proton fraction, which is astrophysically relevant yet difficult to distinguish from helium. Moreover, the main hadronic interaction models predict observably different longitudinal profiles. Hence, measuring these would be helpful in constraining hadronic physics beyond energy levels in man-made accelerators.
