Combined, normalised ESPRESSO spectrum (black histogram) in the right region of the z_abs = 1.1508 absorber, for the strongest transitions only (the weak transitions are shown in Fig. 5). Each panel shows a different transition, as labelled on the vertical axis. The red, solid line represents the fiducial model constructed from the Voigt profile components whose centroids are shown by tick-marks above each transition. We note that the fit traces the data so closely that the former almost obscures the latter in most places. To assist visualising any discrepancies, the normalised residuals (i.e. (data–model)/1σ uncertainty) are shown above each transition (black line) with the ±1σ deviations marked by the green horizontal lines. Top panel: composite residual spectrum; that is, the average normalised residual spectrum of the transitions shown, in units of standard deviations. The data missing from Mg II λ2803, Fe II λ2586, and Fe II λ2344 were excised manually due to the presence of additional absorption, though only the latter is confirmed to arise from a known absorber; see text for discussion.