Differential brightness temperature of warm halos (T_b ≈ 280 K) in the base rotational lines of molecules H₂, HD, and HeH⁺ (from top to down) with and without of the first light: solid dark line – without first light, solid red and blue lines with background first light which reionize the medium at z = 6 and z = 8 accordingly, dotted and dashed blue lines with the first light with energy density 10³ and 10⁶ times higher than the background one (z_rei = 8). In the left column, the first light is Ia, in the right one it is Ib.