Size (R_bubble) of the ionized bubble created by the combined emission of the BDF pair, as a function of the maximum stellar age of the stellar population for BEAGLE SED models within 95% c.l. from the best fit. The cases for escape fraction f_esc = 0.1,0.4, and 0.8 are shown as squares, circles, and stars, respectively, with colour indicating the relevant, total, SFR of the system. The horizontal black line marks the minimum HII size R_min = 1.1 Mpc that would enable Lyα to escape. The dark grey line indicates the minimum HII size R_min = 0.85 Mpc in the case Lyα is affected by a 220 km s⁻¹ outflow. Vertical lines, from left to right, indicate formation redshifts z = 9, 12, and 20.