Angular 21 cm Power Spectrum of a Scaling Distribution of Cosmic String   Wakes
  Cosmic string wakes lead to a large signal in 21 cm redshift maps at redshifts larger than that corresponding to reionization. Here, we compute the angular power spectrum of 21 cm radiation as predicted by a scaling distribution of cosmic strings whose wakes have undergone shock heating. 
Oscar F. Hernandez, Yi Wang, Robert Brandenberger, Jose Fong
astro-ph.CO gr-qc hep-th