Extended Data Fig. 5: A full view of the X-shooter spectrum of J 012555.11−012925.00.

The black, purple, green lines show respectively the observed spectrum, the quasar composite spectrum from⁶² and the same composite reddened by an SMC-like extinction law with A_V = 0.2 at z = 2.66. The blue solid line depicts the continuum component of the quasar spectrum (i.e. removing emission lines), while the blue dashed line corresponds to this continuum component reddened by the same extinction. The red spectrum is the sum of the reddened continuum and the unreddened emission lines and clearly reproduces much better the emission lines redwards of Ly-α. This indicates that the continuum light from the quasar accretion disc passes through dusty gas, while light from the emission line regions is almost unaffected, implying that dust is confined in much smaller regions. b, c indicate zoom-in on the spectral region around C IV and C III] emission lines. The position of metal absorption lines associated with the proximate DLA are marked by grey ticks and labels.