The Magnetic Field at the Galactic Center: Detection of HI Zeeman Splitting

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Session 116 -- Galactic Center and Diffuse Galactic Emission
Oral presentation, Saturday, January 15, 10:15-11:45, Salon IV Room (Crystal Gateway)

[116.05] The Magnetic Field at the Galactic Center: Detection of HI Zeeman Splitting

R.L.Plante, K.Y.Lo, R.M.Crutcher (UofIL), N.E.B.Killeen (ATNF)

We have used the VLA to search for Zeeman splitting of HI absorption against Sgr A West as a direct measurement of the magnetic field strength along the line of sight. Our preliminary results show that the magnetic field is preferentially pointed toward us in the region of the circumnuclear molecular gas north of Sgr A$^\ast$ with our best detection being $-2.6 \pm 0.3$ mG. This result is consistant with the marginal detections of a negative $B$--field using OH absorption in this same region by Killeen et al. 1992.

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