Schedule Feb 17, 2012
Testing the "Common Mass Scale" of Milky Way Dwarf Spheroidal Satellites
Valery Rashkov (UCSC)

We address the "missing satellite problem" and the "common mass scale" puzzle about the nature of Milky Way (MW) dwarf spheroidal (dSph) satellites using a particle tagging technique to dynamically populate the N-body Via Lactea II high-resolution simulation with stars. Using a stellar mass - subhalo mass relation that strongly suppresses star formation in low-mass systems, we successfully reproduce the dSph luminosity function. We demonstrate that simple prescriptions for assigning stellar populations to collisionless particles can reproduce many properties of the observed MW stellar halo and its surviving dSph satellites, such as their velocity dispersions, sizes, brightness profiles, and spatial distribution. With over 1.6 million stellar particles tagged in post-processing, we then mimic the observations of line-of-sight velocity dispersions of the simulated dwarfs and apply the mass estimation algorithm based on spherical Jeans modeling in order to test the accuracy of this technique. We demonstrate that the mass of a dSph enclosed within its inner 300pc can be estimated accurately to within 20% of its true value.


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