2011MNRAS.412..585C

Photometric data from the literature are combined with triaxial mass models to derive the variation in the intrinsic shapes of the light distribution of elliptical galaxies NGC 720, 2768 and 3605. The inferred shape variation is given by a Bayesian probability distribution, assuming a uniform prior. The likelihood of obtaining the data is calculated by using an ensemble of triaxial models. We apply the method to infer the shape variation of a galaxy, using the ellipticities and the difference in the position angles at two suitably chosen points from the profiles of the photometric data. The best-constrained shape parameters are found to be the short-to-long axial ratios at small and large radii, and the absolute values of the triaxiality difference between these radii. The elliptical galaxies of our present investigation are very flat, with ellipticity typically around 0.3 or more. We find that the expectation values of the short-to-long axial ratio of these galaxies are around 0.5.