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Dark-Matter Halos of Early-Type Galaxies

Philip J. Humphrey·David A. Buote·Fabio Gastaldello·Luca Zappacosta·James S. Bullock·Fabrizio Brighenti·William G. Mathews
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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.

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Philip J. Humphrey, David A. Buote, Fabio Gastaldello, Luca Zappacosta, James S. Bullock, Fabrizio Brighenti, William G. Mathews. 2005-10-28. Dark-Matter Halos of Early-Type Galaxies. https://arxiv.org/abs/astro-ph/0510819

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