A dark disc in the Milky Way

Abstract

AbstractPredicting the flux of dark matter particles through the Earth is vital for current and future direct dark matter detection experiments. To date, such predictions have been based on simulations that model the dark matter alone. Here we make the first attempt to include the influence of the baryonic matter. We show that the presence of a stellar/gas disc at high redshift (z ∼ 1) causes merging satellites to be preferentially dragged towards the disc plane. This results in an accreted stellar disc, and a dark matter disc that contributes ρDDISC = 0.25–1 ρHALO at the solar position. Although not likely to be dynamically interesting, the dark disc has important implications for the direct detection of dark matter because of ist low velocity with respect to the Earth. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)