Neutral hydrogen (HI) is a key ingredient in galaxy formation and an excellent tracer of galaxy evolution and the environmental drivers thereof. HI volume density varies significantly with environment, where denser ...

Diffuse radio sources are best studied at low radio frequencies (<~ 1 GHz) as they typically have steep radio spectra, resulting in higher flux densities at lower frequencies. However, this requires high surface brightness ...

Modern and future radio surveys performed with increasingly powerful instruments, such as the 64-antenna MeerKAT interfereometer and eventually the Square Kilometre Array (SKA), will catalogue upwards of hundreds of thousands ...