Ionizing continua for the scenario of fixed log Q(H⁰) = 49.87. Different lines correspond to different shapes of the ionizing continuum, as explained in the text. Note the small differences among the results of synthesis models (labelled as IMF) and the continuum of a 50 M_⊙ and 100 M_⊙ star, consistent with the similarity in  between the cluster and star.