System-by-system median absorption spread versus transverse velocity dispersion. Errors result from a bootstrapping analysis (Sect. 5). Circle areas are proportional to the absorber-plane mean spaxel area (in square kiloparsecs), and colors indicate the median rest-frame equivalent width per system (in Å). σ_∥ has been corrected for the instrumental profile width (Sect. 5), and σ_⊥ has been corrected for the spurious dispersion induced by each system’s S/N selection function (Appendix D).