al. 2003 and Amram et al. 2003, the value for R$_{25}$ was taken from de Vaucouleurs et al. 1991, the RC3, resulting in slightly different numbers from those used here). In order to obtain a V$_{max}$ for use in the T-F relation (represented by a black dot in each subpannel of Figs. 1a and 1b) we have computed the maximum velocity of the average velocity curve (single average of the values for the receding and approaching sides). V$_{max}$ is not the best kinematic parameter to be used in the T-F relation, since V$_{flat}$, the velocity of the flat portion of the curve or V$_{2d}$, the velocity at two times the galaxy scale length are known to yield less scatter in the T-F relation. However, the use of V$_{max}$ allowed us to use the largest possible number of compact group galaxies.

The control sample used for the T-F comparison was the sample of Sb and Sc galaxies from Courteau (1997), where we used their “Vmax” as the equivalent to the maximum velocity determined by us. We also used the sample of galaxies in the Ursa Major cluster (Verheijen 2001), in order to fill in the lower end of the mass sequence 