On the origin of the color Tully-Fisher and color-magnitude relations of disk galaxies

We propose and show that the dependence of the internal face-on dust absorption upon B-band luminosity reported by Wang & Heckman (1996) for a sample of late-type galaxies may explain the empirical color-magnitude and color Tully-Fisher relations of disk galaxies. Thus, in order to explain these relations, it is not necessary to evoke star formation and gas infall efficiencies dependent on the mass of the galaxy system. After applying the Wang & Heckman’s luminosity-dependent extinction to hierarchical inside-out galaxy formation and evolution models where the star formation and gas infall efficiencies do not significantly depend on mass, we succesfully predict the observed Tully-Fisher relations in the H and B bands as well as the color-magnitude relation.