Ratio of baryonic to observed rotation velocity at 2.2 disk scale lengths (V_2.2/V_obs). We show the covariance with the total [3.6] luminosity (top) and effective surface brightness (bottom). Two different normalizations of ϒ_⋆ are illustrated. Galaxies are color-coded by Hubble type. In these plots we exclude galaxies with i < 30° and Q = 3. Large and small circles correspond to galaxies with Q = 1 and Q = 2, respectively. The dashed line shows V_bar/V_obs = 1, denoting the upper limit for physically acceptable disks.