© Sonia Ghosh

On Monday, Emilio Ceccotti defended his thesis named "Precision modelling of the radio sky for 21-cm cosmology with LOFAR". Emilio is part of the LOFAR Epoch of Reionization (EoR) team, and his thesis contains several significant steps towards Epoch of Reionization results with LOFAR. He wrote a new algorithm to — for the first time — integrate accurate, physical spectral information into sky models used for calibration. He also investigated the contribution of modelling errors, and made several new models for the brightest sources that challenge EoR results with LOFAR. Some of these models are already in active use by other teams, and his Cygnus A model has become the default model in the LOFAR Initial Calibration pipeline (LINC). In his final chapter, he publishes first results for the 3C 196 field, which turns out to do better than our main field (NCP), and this is therefore an important result. His thesis focused both on technical and scientific parts, and the opposition asked questions on a wide variety of topics. Emilio's PhD project was supervised by André Offringa (ASTRON), and his promotor was Leon Koopmans (University of Groningen).