2dF b_j band luminosity density profiles of the SW (left panel) and PC (right panel) along the H2356-309 sight line (solid black lines) together with 1σ uncertainties (blue regions). The horizontal (green dashed line) indicates our adopted lower LD threshold LD_bj,min = 0.05 × 10¹⁰L_⊙ Mpc^-3 for extracting the data for further analysis. The vertical dashed lines indicate the best-fit heliocentric redshifts of the Chandra X-ray lines, while the dotted lines bracket the statistical 1σ uncertainties of the redshifts (from F10 and Z10). The co-moving distances refer to the CMB rest frame.