Fermi Gamma-ray Space Telescope

The Smith Cloud and its dark matter halo

Nestor Mirabal
M. Nichols, O. Agertz, F. J. Lockman, J. Bland-Hawthorn

Abstract:

The Smith Cloud is an extraordinary gas structure with a cometary tail being accreted onto the Galaxy. Using hydrodynamical simulations, we find that it could not have survived a passage through the Galactic disc unless the cloud is encapsulated by dark matter. As it stands, the Smith Cloud might represent the best testing ground for dark matter content and confinement in these puzzling gaseous systems surrounding our Galaxy. We determine flux upper limits to the gamma-ray emission around a hypothesized dark matter core in the Smith Cloud, and set constraints on the dark matter annihilation cross section.