Effects of varying Pop III galaxy parameters on the 21 cm global signal (top) and power spectrum (bottom, at k = 0.1 Mpc⁻¹). From left to right, we vary f_R,III, L_X,III < 2 kev, f_esc,7, f_⋆, 7 and A_LW, respectively. The black solid lines correspond to the fiducial values used to compute Fig. 1, while the green (red) solid lines show the result from increasing (decreasing) each parameter while keeping the others fixed. The global 21 cm signal reported in B18 is shown in the top panels with blue dashed lines. In Δ₂₁² panels the magenta dashed lines show the forecasted SKA sensitivity at k = 0.1 Mpc⁻¹ (Barry et al. 2022).