The Physics of CMB Foregrounds: From Spinning Dust to Annihilating Dark Matter

Greg Dobler, CfA

Abstract
Precision measurements of the CMB by WMAP have transformed our view of the Universe in recent years. However, between us and the CMB lies our Galaxy which produces microwave emission that is as bright or brighter than the CMB through all WMAP bands. Although this emission is most commonly regarded as a nuisance for studying cosmology, it contains a wealth of information about the content of the interstellar medium and can be used to study such disparate physics as the geometry and composition of dust grains to the fundamental nature of dark matter. I will discuss our technique for extracting the spectra of foreground emission in the WMAP data and describe how these indicate some surprising features in the Galactic microwave sky, including concrete evidence for rapidly rotating dust grains (spinning dust) as well as excess synchrotron towards the center of the Galaxy. This excess is termed the "haze" and its origin is unknown, though I will show that a generic self-annihilating particle dark matter model is consistent with the data.