Just as Fig. 2, but now with photodetachment of H⁻ ions by the background radiation field, assumed to be described by a blackbody spectrum with a temperature of T_rad = 10⁴ K (left panel) and 10⁵ K (right panel), included. The values of J₂₁ shown in each panel bracket the critical values required to maintain the temperature at ~10⁴ K at a density of 10⁵ cm^-3 that are inferred both with and without Lyman α feedback included, as summarized in Table 1. The case shown here assumes ℬ = 1, corresponding to uniform Lyman α emission within the collapsing cloud.