Background intensity of LW radiation (J_LW) produced by accreting high-z PBH sources. The format of panels, colours, and line styles is identical to Fig. 3: each column corresponds to a different PBH mass, colours represent f_PBH values, and line styles denote the density profiles considered (simple isothermal, Makino+1998, and Liu+2022). The grey dashed line represents the critical value J_LW ∼ 1, where the destruction rate of H₂ equals the formation rate, while the orange dashed-dotted line shows the contribution from stellar sources for reference. The bottom row illustrates the relative contributions of halos ($J_{\mathrm{LW}}^{\mathrm{h}}$) and the IGM ($J_{\mathrm{LW}}^{\mathrm{IGM}}$) to the total LW background intensity ($J_{\mathrm{LW}}^{\mathrm{tot}}$). These are represented as $J_{\mathrm{LW}}^{\mathrm{h}}/J_{\mathrm{LW}}^{\mathrm{tot}}$ (dashed-dotted lines) and $J_{\mathrm{LW}}^{\mathrm{IGM}}/J_{\mathrm{LW}}^{\mathrm{tot}}$ (solid lines), respectively. The relative contributions are computed using the same PBH masses and density profile configurations as in the top row. For f_PBH > 0.0001, the halo contribution dominates at all redshifts, while for f_PBH = 0.0001, the IGM contribution becomes significant at smaller redshifts, especially for larger PBH masses.