Magnetic fields in cool clouds within the central 50 parsecs of the Galaxy.
CHUSS D.T., DAVIDSON J.A., DOTSON J.L., DOWELL C.D., HILDEBRAND R.H., NOVAK G. and VAILLANCOURT J.E.
Abstract (from CDS):
We report the detection of polarized emission in the vicinity of the Galactic center for 158 positions within eight different pointings of the Hertz polarimeter operating on the Caltech Submillimeter Observatory. These pointings include locations 2' offset to the east, northeast, and northwest of M-0.02-0.07; locations to the southeast and northwest of the 20 km/s cloud (M-0.13-0.08); CO 0.02-0.02, M0.07-0.08; and M0.11-0.08. We use these data in conjunction with previous far-infrared and submillimeter polarization results to find that the direction of the inferred magnetic field is related to the density of the molecular material in the following way: in denser regions, the projected field is generally parallel to the Galactic plane, whereas in regions of lower density, the field is generally perpendicular to the plane. One possible explanation for this result is that an initially poloidal field has been sheared into a toroidal configuration in regions that are dense enough such that the gravitational energy density is greater than the energy density of the magnetic field. Another possibility is that winds due to supernovae in the central molecular zone are responsible for deviations from a toroidal field outside of the densest molecular regions.
ISM: Dust, Extinction - Galaxy: Center - ISM: Magnetic Fields - Submillimeter - Techniques: Polarimetric