(a): P_rot–σ_vz relations for individual G_BP − G_RP bins using the method described in Section 3.2. (b): Ro–σ_vz relations, where Ro ≔ P_rotτ_c. Ro is converted from P_rot in (a) using the convective turnover time, τ_c, calculated with a relation described in V. See et al. (2024). The red solid line shows the critical Rossby number where weakened magnetic braking is in effect (Ro_crit = 1.866; J. L. van Saders et al. 2016; N. Saunders et al. 2024). The sections corresponding to the the features are shown on the figures.