Reconstructing large scales at cosmic dawn

The cosmic microwave background (CMB) serves as a backlight to large-scale structure during the epoch of reionization, where Thomson scattering gives rise to temperature anisotropies on small angular scales from the kinetic Sunyaev Zel'dovich (kSZ) effect. In this paper, we demonstrate that the technique of kSZ tomography (velocity reconstruction), based on cross-correlations between CMB temperature and 21-cm surveys, can significantly improve constraints on models of inhomogeneous reionization and provide information about large-scale modes that are poorly characterized by 21-cm measurements themselves due to foreground contamination.

Automated summary

In this paper, we demonstrate the effectiveness of kSZ tomography technique based on cross-correlation between CMB temperature and 21-cm surveys in improving constraints on models of inhomogeneous reionization and providing information about large-scale modes.