Gaussian line width, σ, of warm molecular gas in 3C 326 N as a function of radius. The minimal line widths observed in H₂ 1–0 S(3) and H₂ 0–0 S(3) at spatial resolutions corresponding to 190 pc and 530 pc, respectively, are shown as large, upward-pointing arrows. The broadest line widths observed in both lines are > 1000 km s⁻¹, and fall well outside the plot. Black dots show previous SINFONI observations of H₂ 1–0 S(3) at kpc-scale resolution. The red dotted line shows the position of gas clouds with α_vir = 1, for the gas-mass surface densities observed in 3C 326 N. Light blue circles show molecular clouds in the Milky Way. The yellow band indicates the range where the data should fall if the Larson (1981) scaling relations of turbulent clouds apply. The blue line indicates where the lines should fall for typical mass-to-light ratios of gas cooling through turbulent dissipation. See text for details.