Abstract
Optical rotation curves are presented for the innermost portions of nine spiral galaxies in the Virgo Cluster. The emission-line (Hα and [N II]) velocity data are to be used in combination with new CCD photometry to construct luminosity-velocity diagrams, in a continuing investigation of an apparent initial linear branch and its potential as a distance indicator. Compared to recent H I data, our optical rotation curves generally show systematically steeper inner gradients. We ascribe this effect to the poorer resolution of the H I data and/or to "holes" in the gas distribution. Differences between emission-line and absorption-line rotation curves found, by other workers, for the innermost regions of some spirals, containing significant bulge components, are noted and briefly discussed.
Published Version
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