CANCELLED

Joint Astrophysics Colloquium

The Magnetic Interstellar Medium and the Polarized Dust Foreground

Susan Clark

IAS

The interstellar medium (ISM) is multi-phase, turbulent, and magnetic. This makes the ISM an ideal laboratory for studying the multi-scale physics of star formation and galactic evolution. This unfortunately also makes the ISM a formidable foreground for cosmology experiments, such as the search for inflationary gravitational wave B-mode polarization in the cosmic microwave background (CMB). I will discuss recent work on magnetic fields in the diffuse ISM, with a focus on insights from high-dynamic range observations of neutral hydrogen and polarized dust emission. Novel tools for quantifying the morphology of interstellar material are enabling new probes of the ambient magnetic field structure, and a better understanding of how the magnetic field is linked to the phase structure of the ISM. We are using these insights to build models of the polarized dust emission from the three-dimensional ISM. These also constitute data-driven models of the polarized foreground to the CMB: the search for primordial signals is now inextricably linked to our understanding of the magnetic ISM.