Amplitude of the assumed fiducial UVB at 13.6 eV in standard units of 10⁻²¹ ergs s⁻¹ cm⁻² sr⁻¹ Hz⁻¹. Shown are the quasar (dashed line) component ﹩I_{21,q}﹩, the stellar (dotted line) component ﹩I_{21,*}﹩, and their sum (solid line) at the hydrogen Lyman edge for ﹩\beta _{*}=\beta _{q}=1﹩. For comparison we also plotted the total UVB from Abel & Haehnelt (1999; dash‐dotted line).