Top: Three redshift-corrected spectra in the visible range. Bottom: Three redshift-corrected spectra, with the continuum and iron lines subtracted shown. The X-shooter spectrum is composed of three sections, but here we report only the one useful for the comparison with the SDSS and MUSE spectra. In both panels, we present the SDSS spectrum in light blue, the X-shooter spectrum in blue, and the MUSE spectrum in magenta. The vertical lines correspond to the identified optical lines with a significance > 5σ in all the spectra, except for [O III]λ5007, which was included even though it was not detected in the SDSS spectrum.