Flux density (f_λ) normalized to the area below the curves of the Lyα (black dots) emission line. We present the 1D-stack line of the subsample of the galaxies with EW(Lyα) ≥ 27 Å on the top and with EW(Lyα) < 27 Å on the bottom panel. In the left panels, we show the symmetric (red) and asymmetric (green) Gaussian best fits. In the right panels, we show the best fits of the 100 realizations of the same line generated to calculate the bootstrap uncertainties. For the EW(Lyα) ≥ 27 Å subsample, the Lyα peak shift from the symmetric (asymmetric) Gaussian fit is 196 ± 60 km s^-1 (163 ± 63 km s^-1). For the EW(Lyα) < 27 Å subsample, it is 510 ± 98 km s^-1 (516 ± 114 km s^-1) for the symmetric (asymmetric) Gaussian fit.