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The Far-Infrared Polarization Spectrum: First Results and AnalysisWe present data on the polarization of the thermal emission from Galactic Clouds at 60 micrometers, 100 micrometers, and 350 micrometers. There are examples of rising polarization spectra in dense cloud cores [P(350 micrometers/P(100 micrometers) approximately equal to 2], and falling spectra in cloud envelopes [P(350)/P(100 micrometers) approximately equal to 0.6]. We also present data showing that the relationship, P(tau), between polarization and optical depth in cloud cores is different from that in cloud envelopes. We review the principles governing the far-infrared polarization spectrum and discuss applications to the data on P(lambda) and P(tau). We conclude that the cloud envelopes we have observed must contain two populations of grains that differ in their polarization efficiencies and in their emission spectra. We propose a model for cloud envelopes in which the contrasting populations reside in domains of different mean temperatures where the warmer domains contain the aligned grains.
Document ID
20000057410
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hildebrand, R. H.
(Chicago Univ. Chicago, IL United States)
Dotson, J. L.
(Search for Extraterrestrial Intelligence Inst. Moffett Field, CA United States)
Dowell, C. D.
(California Inst. of Tech. Pasadena, CA United States)
Schleuning, D. A.
(Chicago Univ. Chicago, IL United States)
Vaillancourt, J. E.
(Chicago Univ. Chicago, IL United States)
Date Acquired
August 19, 2013
Publication Date
May 10, 1999
Publication Information
Publication: Astrophysical Journal
Publisher: American Astronomical Society
Volume: 516
Subject Category
Astrophysics
Funding Number(s)
CONTRACT_GRANT: NSF AST-96-19186
CONTRACT_GRANT: NSF AST-97-32326
CONTRACT_GRANT: NCC2-647
CONTRACT_GRANT: NAG2-1081
CONTRACT_GRANT: NSF AST-96-15025
CONTRACT_GRANT: NAG2-1059
Distribution Limits
Public
Copyright
Other

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