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| Paper: |
Polarization of FIR/Sub-mm Dust Emission |
| Volume: |
309, Astrophysics of Dust |
| Page: |
515 |
| Authors: |
Hildebrand, R.; Kirby, L. |
| Abstract: |
Thermal emission from dust in typical molecular clouds is measurably polarized at almost every point. The maximum degrees of polarization in dense clouds at 100 μm are roughly consistent with the maximum values of polarization per optical depth seen in absorption of starlight in the tenuous intercloud medium. Apparently the mechanism of dust alignment is efficient over a wide range of densities, temperatures, and radiation fields. The degree of polarization depends strongly on wavelength in the far-infrared and submillimeter. We attribute the wavelength-dependence in that part of the spectrum to sampling different populations of dust at different wavelengths. Dust emission in the intercloud medium is presumably free of most of the complications encountered in molecular clouds. New instruments are making it possible to examine the spectral energy distributions of infrared cirrus clouds and to extend the measurements to microwave frequencies. In this paper we present new data from WMAP. Measurements of the polarization spectrum in cirrus clouds should become feasible and permit independent tests of dust models. |
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