Evolution of the Lyα and ISM offsets with redshift. We report individual measurements for our sample (filled and empty symbols indicate Δ_Lyα and Δ_ISM, respectively), and for galaxies at z ∼ 7 (green triangles, from Pentericci et al. 2016; Bradač et al. 2017; Matthee et al. 2019). Red and blue circles indicate the average values of Δ_Lyα and Δ_ISM for different samples at different redshifts: the values at z ∼ 2.3 are from Steidel et al. (2010); at z ∼ 2.3 (for the ISM alone) they are from Talia et al. (2017); at z ∼ 3 they are from the stacked spectrum in Shapley et al. (2003); at z ∼ 3.5 they are from Marchi et al. (2019); at z ∼ 4.5 and 5.5 they are from this work; and at z ∼ 7 they are for Lyα alone from Pentericci et al. (2016), Bradač et al. (2017), and Matthee et al. (2019). The blue and red continuous lines are linear best fits to the points. In the bottom panel we also report second-degree polynomial fit that also incorporates the z ∼ 7 data well.