Simulation of the radiative transfer of the Fe II UV1 multiplet. As input source we cast a flat UV continuum (λ = 2570 − 2640 Å) propagated through a galactic wind. In our idealised model the gas velocity (v(r)∝r) increases from 0 to 100 km s⁻¹ and the density profile is described by a power law (ρ(r)∝r⁻³) normalised to an integrated Fe II column density of 10¹⁷ cm⁻². The Doppler parameter, accounting for thermal turbulent motions, is set to b = 30 km s⁻¹. Top: emergent spectrum of the Fe II UV1 multiplet composed of two absorption features and three emission lines (black line). The vertical solid lines show the rest-frame wavelengths of the two resonant transitions (2586, 2600 Å), while the dashed lines show the three associated fluorescent emission lines (≈2612, 2626, and 2632 Å). The red curve shows the Gaussian smoothed spectrum assuming FWHM = 1.2 Å. Bottom: projected image colour-coded by surface brightness (right) and radial surface brightness profile (left) at λ = 2570 − 2640 Å (in arbitrary units). The total surface brightness profile is represented by the solid black line, and the coloured dashed lines correspond to photons that scattered 0, 1, > 1, > 2, and > 5 times. The image of the extended emission (right panel) has been convolved with a Gaussian assuming a PSF full width at half maximum of 0.1″.