Column density N_ion (top panel) and turbulent velocity, σ_v, (bottom panel) plotted versus the flow velocity, v, of the intrinsic UV absorption lines detected in the SUBWAYS HST sample. The data points correspond to the best-fit parameters of Table A.2. The σ_v is calculated from the FWHM of the absorption line according to . The Spearman’s rank correlation coefficient, r_s, and the null hypothesis probability, p_null, are given in the inset. There is a statistically significant correlation between N_ion and v, even including the four outlier data points on the far left, which belong to only one object (PG 1307+085). All data points with a positive value for v (i.e., inflow) belong to only one component of one object (Comp. 1 of PG 0804+761). All other targets show only outflows.