The magnetic field of the Milky Way: OH maser Zeeman results

Abstract

We report on observations with the VLA designed to map precisely the OH maser emission from many interstellar OH sources. ^The primary purpose of these observations is to locate oppositely polarized Zeem%2pairs and measure the strength and line-of-sight orientation of the magnetic field in the masing regions. ^The magnetic fields of interstellar OH masers appear to be of Galactic origin and can be used to map the global structure of the magnetic field of the Milky Way. ^Measurements of the line-of-sight direction of the magnetic field for 34 OH maser sources favor axi-symmetric (over bi-symmetric) models of the magnetic field of the Milky Way.