Evolution of the optical depth for each sample of our galaxies and comparison with QSO data. More IGM transmitted galaxies are shown by the blue stars, less transmitted galaxies are shown as red stars, and black star represent the full sample of our galaxies. Dashed lines represent the fit to each sample and are plotted in the same colors. We also show data from the literature with measurements from Dall’Aglio et al. (2008) as green diamonds, from Faucher-Giguère et al. (2008) as pink triangles, from Becker et al. (2013) as light blue squares, and from Becker et al. (2015) as empty gray circles. The orange point is based on galaxy data from Monzon et al. (2020). The solide purple line is the theoretical model from Meiksin (2006).