Blue end of the OSIRIS/R1000B spectrum of the bright Lyman-α marked S in Fig. 2. The top panel shows the two-dimensional spectrum and the bottom panel the extracted one-dimensional spectrum. A single bright emission line was detected at 3937.8 ± 0.4 Å on top of a blue continuum. The inset shows a zoom-in on the line where the dotted line shows the position of Lyman-alpha centred at z = 2.2261.