Ionization parameter vs. velocity of N V-bearing components with respect to the bulk of the neutral gas (left panel) or the quasar systemic redshift (right panel). Ionization parameters were derived from N V together with Si IV (circles and lower limits) or C IV (squares). The top panels show the velocity distribution of C IV (empty histograms) and N V (gray histograms) as well as subsamples created based on the derived ionization parameter. Some C IV components do not exhibit N V. In the left panel, points are color-coded according to the velocity normalized to that of the neutral gas, as used by Fox et al. (2007) to define whether a high-ionization component is likely gravitationally bound to the DLA (|v| < 2.4 Δv₉₀) or not (see text).