Impact of the observational errors. Top row: fraction of GMM clusters, f_GMM, derived from the number of clusters found by GMM in each error pair, divided by the number of GMM clusters in the no errors case (339). Second row: fraction of clusters for which we derived ages, f_ages, normalized to 339. Red, blue, and black lines are for n_eva, 70 bins of 5–9, 10–19, and 20+ stars, respectively. Third row: ϕ_eva. Bottom row: σ_eva. Columns correspond to different 3D position errors, σ_p, and the x-axis is the 3D velocity error, σ_v.