Surface photometry of dwarf galaxies in Virgo

We compute the intensity-weighted mean ellipticity, the mean deviations from elliptical isophotes, and a newly defined parameter to measure isophotal twists. We also fit each major-axis profile to a power law {Sigma}(a) {prop.to} exp[-(a/a_s_)^n^], where n is allowed to vary.

Consistent with other studies of the Virgo dwarf ellipticals, we find that the profile shapes for the entire sample is strongly peaked near n=1 (exponential profiles) and that no galaxies have n=1/4 (de Vaucouleurs profile). The faintest galaxies all have nearly exponential profiles, while the brighter ones on average have n<1. The correlation between ellipticity and the boxy/disky parameter is similar to that of large elliptical galaxies, suggesting that dwarfs may also be divided into two groups with differing internal dynamics.