1998AJ....116.1125G

A study of mass distributions in 22 spiral galaxies, with rotation curves taken from the literature and Hubble types ranging from Sa to Sd, is presented. It is demonstrated that a relation of the form M_d(r)=γM^1/2(r) between the mass distribution of the luminous components M(r) and that of the dark halo M_d(r) is consistent with the observed kinematics with only the dark-to-visible mass ratio displaying significant variations between galaxies. The parameter γ, which is correlated with M_dyn/M_lum, characterizes the relative importance of the dark-to-luminous mass. The model M/L ratio of the stellar component, M/L_B(stars), is correlated with the observed B - V color. In our sample the average model <M/L_B(stars)> of Sb galaxies is 2.7 M_☉.L^–1_☉ for an average color <(B - V)₀> = 0.71, that of the Sc's is <M/L_B(stars)> = 1.5 M_☉.L^–1_☉ for <(B - V)₀> = 0.54, both values being in very good agreement with population synthesis models. A large part of the intrinsic scatter in the Tully-Fisher relation is due to the spread in γ. The relation of coupling accounts for the disk-halo conspiracy in HSB spirals and is also valid in LSB dwarf galaxies. Its universality in disk rotating systems implies the existence of a physical mechanism responsible for the continuity between visible and dark mass distributions.