Theoretical Physics Colloquium
Observing the first stars at cosmic dawn with 21-cm cosmology
by Prof. Rennan Barkana (Tel Aviv University, Isreal)
Tuesday, September 15, 2020 from to (Asia/Kolkata)
One of the great mysteries in astronomy is the era of cosmic dawn, when the Universe was transformed from a ball of gas to a rich tapestry of stars and black holes. This unique period remains almost completely unknown, but there is now a great international effort to observe it through 21-cm radio waves. The EDGES global 21-cm experiment recently detected the first such signal, finding a much stronger absorption than expected. This absorption can be explained by excess cooling of the cosmic gas induced by an interaction with dark matter. If confirmed, this would have far reaching consequences. We will discuss various predictions for observations with radio telescope arrays, including mapping absorption bubbles around the first galaxies, and detecting the effects of radio emission produced by these same galaxies.