Distribution of f_esc(LyC) for Q1549-C25. f_esc(LyC) is estimated based on the observed ﹩{f}_{900}/{f}_{1500}﹩, an assumed intrinsic ratio, ﹩{L}_{900}/{L}_{1500}=0.20﹩, and 1000 simulated realizations of IGM+CGM transmission in the LyC region at z = 3.15. In each panel, black symbols result from assuming no measurement uncertainty in ﹩{f}_{900}/{f}_{1500}﹩, while blue ones assume the observed error of 0.02. Values of ﹩{f}_{{\rm{esc}}}({\rm{LyC}})\gt 10﹩ (i.e., resulting from low t_IGM) have been fixed at 10, and f_esc(LyC) = 1 is indicated as a vertical dotted line. Left: Histogram of f_esc(LyC) for Q1549-C25. f_esc(LyC)﹩\leqslant ﹩ 1 corresponds to 45% of the realizations. Right: Joint distribution of t_IGM vs. f_esc(LyC). With the assumption of no error bar in ﹩{f}_{900}/{f}_{1500}﹩, there is a one-to-one relation between t_IGM and f_esc(LyC).