LBT-LBC r-band images of the J1030 field. Left: whole field image, with the Chandra coverage shown in green. The spectroscopically confirmed, X-ray-detected members of the z ∼ 2.78 LSS are plotted with a red circle, while the two non-X-ray-detected sources with a MUSE spectroscopic redshift are plotted in red. Non-X-ray sources with a photometric redshift in the range z_phot = [2.68 − 2.88] are plotted as yellow circles. Right: Inset of the ∼4′ × 4′ region (shown as a white box in the left panel) where we detected five out of six members of the LSS. The MUSE coverage of the J1030 field is also shown here for reference.