Envelope (left) and core (right) rotation rates estimated using an ensemble of reference models for different synthetic observations of red giant stars. The comparison with the input rotation rates shows that we are able to recover the underlying rotation rates in all of the synthetic observations. As a fiducial synthetic observation we used a 1 M_⊙ model with solar metallicity, a mixing-length parameter of 1.8, and a large frequency separation of Δν ∼ 15 μHz. For the other synthetic observations, we varied the parameters indicated by the label (see also Table 1). The numerical values of rotation rates and uncertainties are summarised in Table 2. The error given in the dark colours in each panel is calculated from the random and reference model uncertainties by error propagation. The error bar in the light colours is representing the contribution of the random error σ_rand alone. The vertical grey lines indicate the input values.