2008/08/22 by Joachim Stadel, Doug Potter, Ben Moore +5 · 1 citation
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1111/j.1745-3933.2009.00699.x
6 pages, 4 figures, submitted to MNRAS Letters, for full sized images, see http://www.itp.uzh.ch/news.html
arxiv created 2008/08/22 · arxiv updated 2015/05/12
We perform a series of simulations of a Galactic mass dark matter halo at different resolutions, our largest uses over three billion particles and has a mass resolution of 1000 Msun. We quantify the structural properties of the inner dark matter distribution and study how they depend on numerical resolution. We can measure the density profile to a distance of 120 pc (0.05% of Rvir) where the logarithmic slope is -0.8 and -1.4 at (0.5% of Rvir). We propose a new two parameter fitting function that has a linearly varying logarithmic density gradient which fits the GHALO and VL2 density profiles extremely well. Convergence in the density profile and the halo shape scales as N^(-1/3), but the shape converges at a radius three times larger at which point the halo becomes more spherical due to numerical resolution. The six dimensional phase-space profile is dominated by the presence of the substructures and does not follow a power law, except in the smooth under-resolved inner few kpc.