Upper panels: stacks of the Lyα profiles of the LAEVs in the identified overdensities (leftpanel), transition (middlepanel), and field (rightpanel) regions. The green shaded areas indicate the standard deviation of the mean of the fluxes at each wavelength among all the LAEVs in a certain density category. The observed profiles of the LAEVs in overdensity (transition) (field) regions is shown in red (blue) (black) in every panel. The dashed-dotted lines show the median stacks. Lower panels: asymmetric Gaussian curves, best fits of the stacks (dots with errorbars) in the upper panels. In each panel, red is used for the LAEVs in the identified overdensities, blue for the LAEVs in transition regions, black for the LAEVs in the field. The best fits of the asymmetric Gaussian curves provide the following parameters (λ, FWHM, A) = (1215, 4 Å, 0.86), (1215, 3 Å, 0.95), and (1215, 3 Å, 0.83) for the left, middle, and right stack, respectively.