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Astrophysical Masers. 11. Polarization Properties

1973; IOP Publishing; Volume: 179; Linguagem: Inglês

10.1086/151852

1538-4357

Peter Goldreich, Douglas A. Keeley, John Kwan,

Stellar, planetary, and galactic studies

view Abstract Citations (232) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Astrophysical Masers. 11. Polarization Properties Goldreich, Peter ; Keeley, Douglas A. ; Kwan, John Y. Abstract The equations governing the transfer of polarized radiation in astrophysical masers are derived. It is found that the magnetic field and the plasma in maser sources play a central role in determining the polarization of the emitted radiation. The character of the polarization depends upon the relative sizes of the decay constant of the maser levels, F; the stimulated-emission rate R; the Zeeman splitting, g and the bandwidth of the amplified radiation, Aw. Unsaturated masers (R < F) emit unpolarized radiation unless g > Aw. For g > A they amplify the Zeeman pattern if the Faraday rotation per gain length in the source is small. If the Faraday rotation per gain length is large, then the a components of the Zeeman pattern are 100 percent circularly polarized and the n component is unpolarized. Saturated masers (R > F) emit unpolarized radiation unless g > (RF)"2. If the Faraday rotation across the region of saturated amplification is small, the emitted radiation is partially linearly polarized for (RF)"2 < g Aw whereas for g > Aw it is just the amplified Zeeman pattern. If the Faraday rotation across the saturated region is large, all linear polarization is destroyed. For g > Aw, the a components of the Zeeman pattern are again 100 percent circularly polarized. Subject headings: masers - polarization - radiative transfer - Zeeman effect Publication: The Astrophysical Journal Pub Date: January 1973 DOI: 10.1086/151852 Bibcode: 1973ApJ...179..111G full text sources ADS |