Dark-Matter Halos of Early-Type Galaxies
Abstract
Cosmological simulations of galaxy formation predict a universal form for the mass profile of dark matter (DM) halos from cluster to galaxy scales. Remarkably few interesting constraints exist, however, on DM halos in early-type galaxies. Using Chandra we present the temperature, density and mass profiles of a small sample of early-type galaxies, revealing significant DM in each case. When a component is included to account for stellar mass and the DM halo is allowed to respond adiabatically to the baryonic condensation into stars, the mass profiles are well-fitted by the universal profile, with Virial masses and concentrations in agreement with simulations. However, only ~half, or less, of the mass within R_e seems attributable to the stars, implying stellar M_*/L_B ~1-5.
Cite
@article{arxiv.astro-ph/0510819,
title = {Dark-Matter Halos of Early-Type Galaxies},
author = {Philip J. Humphrey and David A. Buote and Fabio Gastaldello and Luca Zappacosta and James S. Bullock and Fabrizio Brighenti and William G. Mathews},
journal= {arXiv preprint arXiv:astro-ph/0510819},
year = {2007}
}
Comments
2 pages, 2 figures, to appear in proceedings of "The X-Ray Universe 2005", San Lorenzo del Escorial, Spain, Sep 26-30 2005