Panel a. The residuals of the OH–SB relation for the B band at the center of the disk as a function of the disk scale length h_B. The points indicate the values of the individual galaxies. The solid lines are linear best fits to those data. The dotted lines show zero lines. Panel b. The same as panel a but for the K band. Panel c. The residuals of the OH–SB relation for the B band at the optical edge of the disk as a function of the morphological T type. Panel d. The same as panel c but for the K band.