Mass distribution in spiral galaxies. II

The VLA telescope was used to observe the atomic hydrogen emission from the Magellanic Cloudlike satellite surrounding several large spiral galaxies. The disks of these systems were resolved and their rotation masses were determined. The satellite kinematics were analyzed to determine an orbital mass in a volume of an average about 3.5 times that of the disk. Simulations were carried out on models on two kinds of models: those in which the satellite orbits were constrained to remain within the halo and those for which the constraint was not imposed. The most successful models have halo radii three to four times the disk radii of their primaries and their satellites have orbital eccentricities less than 0.3. The ratio of halo mass to disk mass is less than five with an average mass of about three disk masses. The observation that most of the satellites are undamaged militates against model galaxies with large halos and satellites with moderately eccentric orbits. 15 refs