Method to retrieve ΔΠ₁. a) Non-rotating, non-magnetized model as in the first panel of Fig. 1. b) Non-rotating, magnetized model as in the third panel of Fig. 1. In each case, left panels represent the stretched PSD according to the dτ_obs variable (Eq. (15)). Subsamples centered around the p-m modes with a width of 2 − Δν are extracted and plotted in different colors below one another. Vertical positions are chosen so that data do not overlap too much, they are therefore arbitrary. Middle panels: a zoom around the dominant peak in the normalized dτ_obs-LS periodogram associated with the different frequency ranges color-coded on left panels. Curves are thicker within the central peak for better visualization. Vertical dot-dashed lines indicate the measurement of Δτ_obsn on the various frequency ranges. Hatched areas indicate the typical uncertainty δ(ΔΠ₁)_res = 0.6 s on the measurement of ΔΠ₁ from LS-based methods according to the study of Vrard et al. (2016), centered around ΔΠ₁ = 75.2 s (same in the right panels). Right panels such local measurements of Δτ_obsn are transferred as a function of the central p-m frequencies. The black line indicates the true value of ΔΠ₁ and the blue dash-dotted line indicates Δτ_obs. In the bottom panel, the dotted pink curve is the result of the Bayesian fit of the ΔΠ₁ − ν_pm law according to Eq. (38), and the pink dash-dotted line indicates the measurement of ΔΠ₁ obtained from the fitting process (see Table 1).