Redshift evolution of Δ_ψ in the ﹩\zeta =500﹩ (thin lines) and ﹩\zeta =90﹩ (thick lines) models. In the latter case, we decrease m_min by an order of magnitude from the default model. The curves are for ﹩\overline{x}_{\mathrm{H}\,}=0.96﹩ (dotted), ﹩\overline{x}_{\mathrm{H}\,}=0.8﹩ (short‐dashed), ﹩\overline{x}_{\mathrm{H}\,}=0.5﹩ (long‐dashed), and ﹩\overline{x}_{\mathrm{H}\,}=0.24﹩ (solid). The redshifts in the two models differ slightly.