Abtract
The 21 cm hyperfine transition of neutral hydrogen is transparent and traces most of the cosmic history, making it a powerful probe of the formation and evolution of cosmic structure. In this talk, I will give an overview of 21 cm cosmology — including the Global 21 cm signal, Epoch of Reionisation tomography, and late-time intensity mapping — highlighting both the scientific motivation and the ongoing experimental efforts, as well as the major challenges that remain. I will also present some of our recent work, from systematic-robust data processing pipelines to new directions in statistical measurements, ranging from ultra-high-dimensional Bayesian inference to dynamical approaches based on one-point statistics for scientific extraction.