A Model for the Magnetic Field in the Molecular Disk at the Galactic Center
Abstract
A model for the magnetic field configuration in the Galactic center disk is presented. The field has an open geometry and represents the poloidal field detected at larger distances from the Galactic center, stretched and twisted by the effects of advection and shear in a magnetized accretion disk. It is concluded that the 100 micron polarization measurements of Hildebrand et al. (1990) imply that the radial and azimuthal components of the magnetic field in the disk are comparable and have opposite signs, consistent with the generation of B(phi) from B(r) by differential rotation. The polarization measurements indicate that the z-component of the field is smaller than both /B(phi)/ and /B(r)/; thus, they do not by themselves require that the field lines thread the disk. The field strengths of order 1 mG inferred from the Zeeman measurements and the fact that /B(phi)/ and /B(r)/ exceed B(z) imply that the field could remove the excess angular momentum of the accreted matter in the form of a centrifugally driven outflow.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1990
- DOI:
- 10.1086/169249
- Bibcode:
- 1990ApJ...362..120W
- Keywords:
-
- Accretion Disks;
- Galactic Nuclei;
- Interstellar Magnetic Fields;
- Magnetic Field Configurations;
- Polarized Radiation;
- Astronomical Models;
- Milky Way Galaxy;
- Radial Flow;
- Zeeman Effect;
- Astrophysics;
- GALAXIES: NUCLEI;
- GALAXIES: THE GALAXY;
- INTERSTELLAR: MAGNETIC FIELDS;
- POLARIZATION