Mass distribution in spiral galaxies

The masses of a carefully selected sample of primary disk galaxies orbited by one or more satellite systems have been calculated both from the rotation of the disks and from the kinematics of the satellites. The ratio of these two mass estimates (chisub(obs)) is sensitive to the presence of any extended halo and for satellite-primary pairs the mass distribution is significantly different from that of binary galaxies. The present data cannot be described by the heavy halo model with circular orbits, though extended haloes are a possibility if the satellite orbits are highly eccentric. (author)