Unfolding the energy spectrum of ultra-high-energy cosmic rays using Pierre Auger open data

We reconstruct the energy spectrum of ultra-high-energy cosmic rays using the public data made available by the Pierre Auger Observatory. We develop a consistent procedure to regenerate the migration matrix and a pseudo-Monte Carlo sample directly from the published quantities. Such a sample allows for the application of both classical unfolding techniques as well as a machine-learning-based ones. We compare the unfolded results to the one published by Auger as well as between the various unfolding techniques applied to the full published raw spectrum as well as the 10% public dataset. We demonstrate that using the publicly available information the presented approach allows for the full unfolding procedure using in principle any future unfolding method based on the migration matrix or event-by-event true-raw levels pairs.