MRC 0251-273. Top: nuclear spectra centered on the Lyα  (left) and CIV + HeII lines (right) extracted from the region shown as black circle in the inset. Middle: left, Lyα  narrowband image extracted from the spectral region shown in the 10”×10” inset; right: Lyα  brightness profile. The black contours mark the 2σ flux limits, and the blue cross is the point from which the brightness profile is extracted. The location of the radio source, unresolved in the VLASS image, is marked with a red cross. Bottom: Voronoi-tessellated maps of velocity and FWHM of the Lyα  line.