High-Resolution Millimeter-Wave Mapping of Linearly Polarized Dust Emission: Magnetic Field Structure in Orion
R. Rao, R. M. Crutcher, R. L. Plambeck, M. C. H. Wright;
ApJ, 1998, 502, L75
ABSTRACT:We present 1.3 and 3.3 mm polarization maps of Orion-KL obtained with the BIMA array at approximately 4" resolution.
Thermal emission from
magnetically aligned dust grains produces the polarization.
Along the Orion
"ridge" the polarization position angle varies smoothly from about 10 deg to 40
deg, in agreement with previous lower resolution maps.
In a small region
south of the Orion "hot core," however, the position angle changes by 90
deg.
This abrupt change in polarization direction is not necessarily the
signpost of a twisted magnetic field.
Rather, in this localized region,
processes other than the usual Davis-Greenstein mechanism might align the dust
grains with their long axes parallel with the field, orthogonal to their
normal orientation.
KEYWORDS: magnetic fields, polarization, instrumentation: polarimeters, techniques: interferometric, stars: formation, ism: magnetic fields
CODE: rao98