F(Lyα)/F([OIII]5007) ratio versus the velocity offset between the same emission line central wavelengths. We present LAEs at z ≃ 2 in blue and at z ≃ 3 in red. The red asterisk is for LBG11. Data from McLinden et al. (2011) and (Finkelstein et al. 2011, updated by Chonis et al. priv. comm.) are shown as circles, from Erb et al. (2010) as triangle. The vertical lines represent the ranges of Δv_{Lyα − LIS} by Shapley et al. (2003) (dashed) at z ~ 3, Berry et al. (2012) (solid) at z ~ 2 and 3, roughly divided by 3 to be compared with Δv_{Lyα −  [OIII] 5007} (see text), and Steidel et al. (2010) (dotted).