Large-scale 21-cm Cosmology with LOFAR and AARTFAAC

The first stars, black holes and galaxies in the virgin Universe appeared and evolved during the so-called ‘Cosmic Dawn’ and ‘Epoch of Reionization’. It is extremely important to study these epochs to understand the properties of these objects and how they interacted with their surrounding medium. Due to lack of direct observations, these epochs are the least studied periods in the history of the Universe, leaving a significant hiatus in our current understanding of the Universe. Observing the so-called ‘21-cm signal’ which is a specific signature of neutral hydrogen from these eras will aid in understanding the physical conditions during the early Universe. The 21-cm Cosmology experiments aim to observe this specific signature. My research focuses on quantifying and solving observational challenges faced by these experiments. In my work, I propose various methods and techniques to overcome these challenges. I also make attempt to measure the 21-cm signature from a specific time period during the Cosmic Dawn using the state-of-the-art LOFAR radio telescope based in the Netherlands. Along with this, I present the very first results from a new project called ‘AARTFAAC Cosmic Explorer’ or ACE which has been commenced to measure the neutral hydrogen signature from the Cosmic Dawn using the AARTFAAC radio telescope.