Impact of Foregrounds on HI Intensity Mapping Cross-Correlations with Optical Surveys

Understand

The future of precision cosmology could benefit from cross-correlations between intensity maps of unresolved neutral hydrogen (HI) and more conventional optical galaxy surveys.

• A major challenge that needs to be overcome is removing the 21cm foreground emission that contaminates the cosmological HI signal.
• Using N-body simulations we simulate HI intensity maps and optical catalogues which share the same underlying cosmology.
• Adding simulated foreground contamination and using state-of-the-art reconstruction techniques we investigate the impacts that 21cm foregrounds and other systematics have on these cross-correlations.