Significance of the flux decrement near Δν = 0. In the left panel, the S/N per pixel is illustrated for different binning windows for the two redshift bins. The gray shadow area corresponds to the fit region, while F_S (σ_S) and F_L (σ_L) represent the (errors on the) flux of the short and long gaps respectively. The right panel shows the significance distribution within the (gray) fit region. The pixels with an S/N larger than 5 are highlighted.