Magnetic Fields in the Milky Way

by S. Ann Mao (University of Wisconsin-Madison)

Wednesday 2 May 2012, 11:00 → 12:00 Europe/Stockholm

122:026

In this talk, I will review observational constrains we have on the magnetic field structure of our own Milky Way. In particular, I will present results from two surveys of Faraday rotation measure of polarized extragalactic sources. Based on rotation measures along 1,000 sight lines towards the Galactic poles, we find a lack of vertical magnetic field symmetry across the Galactic mid-plane. The observed RMs could be the superposition of a symmetric disk field and an anti-symmetric field produced by a separate dynamo effect in the Galactic halo. Furthermore, I demonstrate that existing Galactic halo magnetic field models cannot successfully reproduce extragalactic rotation measures at mid-Galactic latitudes in the second Galactic quadrant. We suggest that halo fields consist of magnetic spirals could potentially account for the observed rotation measure pattern.

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