The magnetic fields in the galactic center: Detection of H1 Zeeman splitting

Abstract

We have measured the Very Large Array (VLA) to search for Zeeman splitting of H I absorption against Sgr A West in order to measure directly the magnetic field strength along the line of sight. We report several directions within the circumnuclear molecular gas about 1 min north of Sgr A*. Our results show that the magnetic field is preferentially pointed toward us in this region with our most reliable detection being -3.0+/-0.5 mG. The highest detected fields appear to be associated with infalling gas rather than the circumnuclear disk itself. We suggest that the average line-of-sight component of the field within the circumnuclear disk as traced by the H I gas is less than 1 mG.