Smoothed 45″ × 45″ Chandra full-band image of the DRC core. The green contours (3σ, 5σ, 9σ) mark the 2 mm continuum emission of the ALMA sources with ≈2″ angular resolution, labeled as in Oteo et al. (2018). The cyan contours (5σ, 7σ, 9σ, 11σ) show the continuum-subtracted LAB emission in a velocity range [ − 1300, 800] km s⁻¹, centered on the Lyα wavelength at z = 4.002. This velocity range encompasses most of the Lyα line profile of the LAB (see Oteo et al. 2018). The entire image is covered by MUSE observations.