Same as Fig. 1, but with line widths inferred from high-resolution spectroscopy replacing data unresolved by SDSS (the unresolved data are still shown as gray dots). The solid green line shows a linear fit to the combined SDSS resolved and high-resolution data. The solid blue line shows the same linear fit to the resolved SDSS data as in Fig. 1, extrapolated to the SDSS-unresolved regime as a dashed line. Targets without detections in CO are marked with vertical line markers on the x-axis at the position corresponding to their Hα line widths inferred from their NTT or TNG spectra. Dotted vertical lines show the approximate SDSS resolution R = 2000 (FWHM ∼ 150 km/s), and the median resolution for the sample achieved with TNG (FWHM ∼ 52 km/s) and NTT (FWHM ∼ 78 km/s) for the Hα line.