Model-independent curvature determination with 21cm intensity mapping experiments

Understand

Recent precision cosmological parameter constraints imply that the spatial curvature of the Universe is essentially dynamically negligible - but only if relatively strong assumptions are made about the equation of state of dark energy (DE).

• When these assumptions are relaxed, strong degeneracies arise that make it hard to disentangle DE and curvature, degrading the constraints.
• We show that forthcoming 21cm intensity mapping experiments such as HIRAX are ideally designed to carry out model-independent curvature measurements, as they can measure the clustering signal at high redshift with sufficient precision to break many of the degeneracies.
• We consider two different model-independent methods, based on `avoiding' the DE-dominated regime and non-parametric modelling of the DE equation of state respectively.