We describe a technique that uses radial color gradients in disk galaxies to detect the presence of bulk noncircular motion or elliptical orbits. In a disk galaxy with both a radial color gradient and non-circular motion, isochromes, or isocolor contours, should follow the shape of closed stellar orbits, and the ellipticity of the isophotes should vary as a function of wavelength. A difference in the duplicity of isochromes and the isophotes can be used to detect the presence of noncircular motion. A model galaxy is constructed which demonstrates this phenomenon. The difference between isochrome and isophote ellipticity is directly related to the ellipticity of the potential. This provides a new way to measure the ellipticity of the dark matter in the outer parts of galaxies. As an example, we apply this technique to two dwarf galaxies, NGC 1800 and NGC 7764. We detect a bar in NGC 1800 which has only previously been suggested from the H I velocity field. In NGC 7764 there is no color gradient along its bar, so we cannot detect noncircular motion in this region; however, ellipticities observed in a star-forming ring at the end of the bar are consistent with this ring being located near the corotation resonance.
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