2D and the 1D spectra of the Lyα extracted from X-Shooter shown in the top and bottom panels. The blue line shows the spectrum of the sky, while the red vertical line (on the 1D spectrum) marks the systemic velocity of the source with the one sigma error (dotted vertical lines), located at +35 km s⁻¹ form the central Lyα peak dubbed 0. The other Lyα peaks are marked as −2, −1 (blueward the systemic velocity), and 1 (redward from systemic velocity).