Have the tides turned for the formation of cE galaxies?
A specific class of elliptical galaxies called compact ellipticals, or cEs, are unusually compressed. Some speculate that these galaxies are petite because their outer layers have been stripped away by a neighboring galaxy; however, an alternative theory claims that these are regular elliptical galaxies that simply formed small and never contained stars in their outer regions. In order to differentiate between these two models, Howley et al. 2012 measured the dynamics of individual stars in one of our nearest neighbors, the compact elliptical M32.