Left: X-ray galaxy group masses, M₂₀₀, as a function of redshift in XMM-LSS, calculated with redMaPPer (grey circles), calculated with the redshift of sources in the XMM-LSS sample that visually coincide with the 0.5–2 keV extended X-ray emission (green triangles, 2D Match) and from cross-matching the X-ray galaxy groups from the ‘2D Match’ to the ones from redMaPPer, given Δz ≤ 0.018 (blue stars, 3D Match). Right: Example of a radio galaxy spatially coinciding with extended X-ray emission. The background is the SDSS i-band data, overlaid with MIGHTEE 8.9″ radio data at 3σ (cyan contours) and 0.5–2 keV extended X-ray emission (white contours). A scale of 100 arcsec in length is shown on the bottom right. This corresponds to 267 kpc at the redshift of the source 178, z = 1.54.