Resonant frequencies of the Ep models calculated in Kerr spacetimes. The enlarged area emphasizes the existence of maxima of the ν_U × M curves in the case of the Ep1, Ep3, and Ep4 models in BH spacetimes. The shaded region corresponds to the observational values of ν_U × M determined for Galactic microquasars (see Sect. 5 for discussion). Panel a: behaviour of resonant frequencies of the whole group of models on a large scale of a. Panel b: detailed view of behaviour of the resonant frequencies for the Ep1 and Ep2 models for a ≈ 1. The individual horizontal grey-scaled areas denote the observational values of ν_U × M determined for each of the Galactic microquasars. Panel c: detailed view of the behaviour of resonant frequencies for the Ep3 model for a ≈ 1. Panel d: detailed view of the behaviour of resonant frequencies for the Ep4 and Ep5 models for a ≈ 1.