Spatial offsets measured in the simulated galaxies. Left: distribution of elliptical distance measured in the source plane between the Lyman-α emission centroids and the ellipse formed by the UV emission distribution (using r_90,UV as radius) for the LLAMAS galaxies (in grey) and the simulated LLAMAS galaxies (in yellow). Right: distribution of the UV-UV spatial offsets measured between the UV emission peak and the UV centroid position in LLAMAS galaxies (in grey) and simulated LLAMAS galaxies in yellow. We show here only the galaxies for which this UV-UV offset is higher than 2 HST pixels in the image plane.