Deprojecting spiral galaxies using Fourier analysis. Application to the Frei sample

Abstract

We present two methods that can be used to deproject spirals, based on Fourier analysis of their images, and discuss their potential and restrictions. Our methods perform particularly well for galaxies more inclined than 50° or for non-barred galaxies more inclined than 35°. They are fast and straightforward to use, and thus ideal for large samples of galaxies. Moreover, they are very robust for low resolutions and thus are appropriate for samples of cosmological interest. The relevant software is available from us upon request. We use these methods to determine the values of the position and inclination angles for a sample of 79 spiral galaxies contained in the Frei et al. (1996) sample. We compare our results with the values found in the literature, based on other methods. We find statistically very good agreement.