ELECTRIC VECTOR ROTATIONS OF π/2 IN POLARIZED CIRCUMSTELLAR SiO MASER EMISSION
ELECTRIC VECTOR ROTATIONS OF π/2 IN POLARIZED CIRCUMSTELLAR SiO MASER EMISSION
复制标题
偏振周星SiO脉泽发射中π/2的电矢量旋转
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
R. Xue
中科院分区：
文献类型：
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作者：
A. Kemball;P. Diamond;L. Richter;I. Gonidakis;R. Xue
This paper examines the detailed sub-milliarcsecond polarization properties of an individual SiO maser feature displaying a rotation in polarization electric vector position angle of approximately π/2 across the feature. Such rotations are a characteristic observational signature of circumstellar SiO masers detected toward a number of late-type, evolved stars. We employ a new calibration method for accurate circular very long baseline interferometric polarimetry at millimeter wavelengths to present the detailed Stokes {I, Q, U, V} properties for this feature. We analyze the fractional linear and circular polarization as a function of projected angular distance across the extent of the feature and compare these measurements against several theoretical models proposed for sharp rotations of electric vector position angle in polarized SiO maser emission. We find that the rotation is most likely caused by the angle θ between the line of sight and a projected magnetic field crossing the critical Van Vleck angle for maser propagation. The fractional linear polarization profile ml(θ) is well fitted by standard models for polarized maser transport, but we find less agreement for the fractional circular polarization profile mc(θ).
