THE MASS-DISTRIBUTION IN DWARF DISK GALAX IES

The masses of the stellar disk, gaseous disk, and dark halo of 13 dwar f galaxies are determined through modeling of their rotation curves. T he mass-luminosity relation for low-luminosity galaxies is constructed , The ratio M(t)/L(b) inside the optical radius approximate to 6, End depends only weakly on luminosity. The relative masses of components a re compared. The contribution of the dark halo in dwarf galaxies is on average 70%, which is nearly a factor of two greater than for galaxie s with ''normal'' luminosity. Models without a dark halo but including massive gaseous and stellar disks were also constructed, in order to test the hypothesis that dark matter is contained in dense, cold molec ular clouds. In the majority of cases, the observed rotation curves ca n be satisfactorily explained in the framework of such a model; howeve r this hypothesis runs into serious difficulties in the analysis of th e gravitational stability of disks.