A MULTIDIMENSIONAL APPROACH TO ESTIMATING PECULIAR VELOCITIES OF GALAXIES

We examine a possibility for improving the estimates of peculiar velocities of galaxies using several distance indicators and several calibrators. Using 39 ellipticals and 120 edge-on spirals, we show that a multidimensional approach is 1.1-1.3 times more accurate than the Faber-Jackson or Tully-Fisher methods. In the case of ellipticals, it turns out that the most effective distance indicator is the stellar magnitude: calibrators for this include the velocity dispersion, the surface brightness, and the color index. In the case of edge-on spirals, it turns out that the best indicator is the diameter of the galaxy in red light: calibrators for this include the H I line width and the ratio of the apparent axes of the galaxy image (there are no color indices). For certain galaxies in our sample, the peculiar velocities estimated from the multidimensional approach are substantially different from those obtained by the Faber-Jackson or Tully-Fisher methods.