Fig. 2
Imaginary part of the solutions of the dispersion relation for two-component disks with η ≈ 0.01 for models without counterrotation (left frame) and η ≈ −1.4 with counterrotation (right frame), where 
and ν are the relevant dimensionless radial wavenumber and the dimensionless Doppler-shifted frequency, respectively (following the notation of Bertin & Cava 2006).
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