Strömberg’s law and asymmetric drift equation adjusted for several subsamples. Top: Strömberg’s law for thin disc subsamples (black dots) accounting for the total velocity dispersion σ² (km² s⁻²) and the velocity moment μ₂₀₀ (km² s⁻²) in terms of their heliocentric rotation velocity V₀ (km s⁻¹). Fitting of Eq. (21) (right panel) for thin disc subsamples (red dots) using the optimal value of γ_c. Bottom: (left panel) Strömberg’s law for the total thin disc (t, red line) and the thick disc (T, black line) subsamples; and (right panel) for thin disc, thick disc, and halo (H) components.