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The authors have analyzed components of the UVW Galactic space motions resulting from the accurate proper-motion surveys of Chiu (1980), which contain several hundred stars complete to V = 20.5 in each of three fields. Two of these fields lie close to the Galactic center - Sun meridional plane, so that derived space motions are nearly independent of the unknown radial velocities. These data show a rotating, intermediate velocity dispersion component of the spheroid, in addition to the well-studied thin (old) disk and the extreme spheroid.
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Wyse et al. (1986) studied this question.
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