Collaborative Research: Unveiling Dark Matter in Dwarf Spheroidal Galaxies

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AST-0507511OlszewskiThough it permeates the entire Universe, dark matter (DM) remains as elusive today as when its gravitational signature was first noted. Fortunately, dwarf galaxies continue to offer a unique window into the nature of DM, as they are host to the smallest known DM structures and may represent the survivors of a vast primordial population. Unfortunately, dwarf galaxy studies rely on observing the motions of individual stars and their interpretation by models, and this is flawed both by having only small samples for any one galaxy, and by requiring highly restrictive assumptions to obtain an answer. It is now possible to obtain samples of thousands of stars in nearby dwarf spheroidal galaxies, where it was previously usual to have only tens of stars. At the same time, new, far more sophisticated non-parametric statistical techniques are being developed, which not only include tests of some of the standard dynamical assumptions, but also may offer ways to relax some of those assumptions. The ultimate goal of this research is a kinematical model with the fewest possible assumptions being confronted with the maximum number of discrete velocities in all of the nearby dwarf spheroidal galaxies.This close collaboration between astronomers and statisticians links researchers at two universities, including students who can continue this collaborative tradition, and serves the entire astronomical community through the provision of new equipment and the widespread availability of the data and the statistical methods. The results will feed into public and K-5 outreach, which are already a regular part of each researcher's activities.