Tentative detection of Lyman-α emission at z = 6.3449. Upper panel: part of the X-shooter 2D spectrum. Wavelengths are reported in the observer frame. Lower panel: 1D spectrum corresponding to the extraction between the black horizontal lines of the 2D spectrum (from −0.8″ to −3.3″). In both panels the tentative Lyman-α emission detection is indicated by the blue lines surrounding it. The red line corresponds to the noise spectrum.