RA and Dec of all galaxies within 8000 and 16 500 km s⁻¹, characterised by velocity groups: 8000 ≤ v < 10 500 km s⁻¹ (grey downward-pointing triangles), 10 500 ≤ v < 12 000 km s⁻¹ (blue circles), 12 000 ≤ v ≤ 15 000 km s⁻¹ (red circles), and 15 000 < v ≤ 16 500 km s⁻¹ (grey upward-pointing triangles). Galaxies from Andreuzzi et al. (1998) and the CID36 region are marked by open squares. The three X-ray concentrations are indicated by large circles centred on the sky coordinates from Table 3, with radii of 30 arcmin for A548E and A548W, and 25 arcmin for CID36.