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Session 8 - Distance Indicators.
Display session, Monday, January 15
North Banquet Hall, Convention Center
Surface brightness fluctuations have been used by Tonry and Schneider (1988) to determine the distances to elliptical galaxies. This method measures the observed mottling in the confusion limited spatial distribution of stars on the ordinary giant branch, which decreases inversely with distance. We have modified the technique so that a smooth fit to the galaxy is not removed from the image, and all information on the stellar distribution with radius is retained. By analyzing 2-D power spectra of images of elliptical galaxies we derive accurate distances.
Test star fields were created to simulate the stellar distributions and the stellar luminosity function in the V and K bands for elliptical galaxies. These simulated star fields were used to test this distance finding method. We have shown that the ratios of radially averaged power spectra yield relative distances among galaxies to within 10%. The slope of the power spectrum over the mid-spatial frequencies gives a direct measure of the distance to the elliptical galaxy as well.
Program listing for Monday