Polarization of far-infrared radiation from molecular clouds
G. Novak, D. P. Gonatas, R. H. Hildebrand, S. R. Platt, M. Dragovan;
ApJ, 1989, 345, 802
ABSTRACT:The paper reports measurements of the polarization of far-infrared emission from dust in nine molecular clouds.
Detections were obtained in Mon
R2, in the Kleinmann-Low (KL) nebula in Orion, and in Sgr A.
Upper limits
were set for six other clouds.
A comparison of the 100 micron polarization
of KL with that previously measured at 270 microns provides new evidence
that the polarization is due to emission from magnetically aligned dust
grains.
Comparing the results for Orion with measurements at optical wavelengths, it is
inferred that the magnetic field direction in the outer parts of the Orion cloud
is the same as that in the dense core.
This direction is nearly
perpendicular to the ridge of molecular emission and is parallel to both the molecular
outflow in KL and the axis of rotation of the cloud core.
In Mon R2, the field
direction which the measurements imply does not agree withthat derived from
0.9-2.2 micron polarimetry.
The discrepancy is attributed to scattering in
the near-infrared.
In Orion and Sgr A, where comparisons are possible,
the measurements are in good agreement with 10 micron polarization
measurements.
KEYWORDS: far infrared radiation, interstellar magnetic fields, interstellar matter, molecular clouds, optical polarization, astronomical maps, carbon monoxide, linear polarization, orion nebula, polarimetry
PERSOKEY:polarisation, fir, molecular clouds, magnetic field, kao, ,
CODE: novak89