a, For the first method, calculating the LyC escape fraction from the Hα luminosity following Eq. (8). b, Following Eq. (10), for the best-fit BPASS model with metallicity Z = 0.004, and an age of the stellar burst of ~ 4.5 × 106 years. Other BPASS models, varying ages, are shown with faded lines for comparison. On both panels, the vertical dashed line shows the value of the escape fraction assuming a transparent IGM (following Eq. (8) and Eq. (10)).