Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

A Dark Matter Bestiary: Cusps, Caustics, and Streams in the Milky Way

Benjamin Monreal
MIT

Tuesday, December 18, 2007
1:30 PM @ Stirling A

Abstract:

There is much we don't know about our home galaxy, the Milky Way; the stars are mapped out in great detail, but 80% of the mass consists of dark matter whose distribution is all but unknown. The dark matter is usually approximated as a smooth, featureless cloud; a rough model for this shape gives us the local dark matter density, 0.3 GeV/cm^3, that motivates underground searches for dark matter nuclear scattering. However, thanks to the Milky Way's complex formation history, a whole bestiary of unusual substructures may exist, some of which are highly relevant to experiments. I will give a tour of three such odd beasts (cusps, caustics, and streams) and show how dark-matter experiments look for each of them. I will show how a Galactic Center cusp could affect the evolution and chemistry of stars, especially dwarf stars; I will also describe a low-pressure gas time projection chamber, DMTPC, whose directional search for dark matter is sensitive to caustics and streams.

Ben Monreal is a short-listed candidate for the faculty position in Experimental Particle Astrophysics. He will be in the Department on Monday Dec 17th and Tuesday Dec 18th.