Example of our spectral decomposition fit (described in Sect. 3) to simulated data of a galaxy that hosts a CON. The left panel shows a highly diluted nucleus (β = 0.42) with a spectrum dominated by star formation, and the right panel shows a CON-dominated source (β = 0.89). The full model, shown in red, is composed of the various components shown in the legend. The continuum is shown as the solid gold line and is a sum of the nuclear and star-forming (SF) components, which are shown as dashed lines. The flux is in arbitrary units. The equation of the full model is given in Eq. (1).