Gravitational Lensing of Cosmological 21cm Emission

Understand

We investigate the feasibility of measuring weak gravitational lensing using 21cm intensity mapping with special emphasis on the performance of the planned Square Kilometre Array (SKA).

• We find that the current design for SKA-Mid should be able to measure the evolution of the lensing power spectrum at z~2-3 using this technique.
• This will be a probe of the expansion history of the universe and gravity at a unique range in redshift.
• The signal-to-noise is found to be highly dependent on evolution of the neutral hydrogen fraction in the universe with a higher HI density resulting in stronger signal.