Intensity mapping with BAO and on large scales

Mapping out HI intensity on a big redshift range will push the boundaries in cosmology in many different ways. I will talk about two novel techniques, using forecasted data for future radio surveys. The first one will allow us to constrain curvature independently of the dark energy equation of state using measurements of baryon acoustic oscillations in both angular and radial direction. Specifically we will look at curvature constraint forecasts for the planned radio interferometer HIRAX. After this I will mention the multi-tracer technique. Combining future HI and galaxy maps, one can beat the cosmic variance limit on certain observables on the largest scales. We demonstrate this in a realistic scenario by analyzing simulated HI intensity and galaxy maps, including instrumental noise and foreground contamination of the HI maps.