Upper panel: Input ionization map (gray neutral, white ionized) at $\overline{x}=0.7$ and M_UV≤-17.2 galaxies (dots) used to calculate asymmetry maps at z = 8. Galaxies are color-coded by their peak Lyα transmission (𝒯) inferred from the observed EW and uncertainty of EW. From left to right we show results using 5σ EW limit, EW_{Lyα, limit} = 10, 30, 50, and 100 Å for the faintest galaxies. Lower panel: Asymmetry maps (red contours) made using the galaxies in the upper panel. We can recover bubble edges very well when EW_{Lyα, limit} is at least the median emergent EW of galaxies (≈30 Å). When EW_{Lyα, limit} is too shallow (≫30 Å), we cannot get useful information about Lyα transmission from our observations, thus the recovered bubbles only trace the regions around galaxies with EW greater than the detection limit.