21-cm Lensing and the Cold Spot in the Cosmic Microwave Background
  An extremely large void and a cosmic texture are two possible explanations for the cold spot seen in the cosmic microwave background. We investigate how well these two hypotheses can be tested with weak lensing of 21-cm fluctuations from the epoch of reionization (EoR) measured with the Square Kilometer Array (SKA). While the void explanation for the cold spot can be tested with SKA, given enough observation time, the texture scenario requires significantly prolonged observations, at the highest frequencies that correspond to the EoR, over the field of view containing the cold spot. 
Ely D. Kovetz and Marc Kamionkowski
astro-ph.CO