The Stellar Populations of dE Galaxies in Nearby Groups

Abstract

In this contribution Gemini-North NIRI J,K-observations are used to investigate the upper-Asymptotic Giant Branch (AGB) intermediate-age population in the M81 Group dwarf elliptical (dE) F8D1. Hubble Space Telescope (HST) `snapshot' V,I-observations are also analysed to investigate the upper-AGB populations in two other M81 Group dEs, DDO 71 and kk077. In all three dEs, significant intermediate-age populations are found. Further, there are sizeable dE-to-dE differences in these populations: F8D1 contains relatively more, and relatively more luminous, upper-AGB stars. These results are compared with existing information for Local Group and Sculptor group dwarfs. It is suggested that `environmental harrassment' plays an important role in governing dwarf galaxy evolution.