Elliptical Galaxy Halo Masses from Internal Kinematics

The halo masses of nearby individual elliptical galaxies can be estimated by using the kinematics of their stars, planetary nebulae, and globular clusters-ideally in combination. With currently improving coverage of galaxies of ordinary luminosities and morphologies, systematic trends may be identified. Bright, boxy ellipticals show strong signatures of dark matter, while faint, disky ones typically do not. The former result is problematic for the MOND theory of gravity, and the latter is a challenge to explain in the ΛCDM paradigm of galaxy formation.