21 cm temperature power spectrum for a few Lyman alpha emission models and simulations S1 and S2. Top black solid lines correspond to  ⟨ x_α ⟩  = 0.4 while bottom dashed/dotted curves to  ⟨ x_α ⟩  = 0.1 (all at z ~ 20.25). The green dot-dashed line uses halos down to 10⁶    M_⊙ and a Pop III type emission spectra. The error bars in blue corresponds to the full SKA while the ones in red to 10% of the collecting area.