A sample of 129 unresolved radio sources with ultrahigh linear polarization (>30 per cent) has been selected from the NRAO VLA Sky Survey. Such high average linear polarization is unusual in extragalactic sources. Higher resolution Australia Telescope Compact Array and Very Large Array observations confirm the high average polarization but find that most of these sources are extended. The Sloan Digital Sky Survey spectroscopy, where available, shows that the optical counterparts are elliptical galaxies with no detectable emission lines. The optical spectra, radio luminosity, linear size and spectral index of these sources are typical of radio-loud active galactic nuclei. Galaxy counts within a 1 Mpc radius of the radio sources show that these highly polarized sources are in environments similar to their low polarization (<2 per cent) counterparts. Similarly, the line-of-sight environments of the ultrahigh polarization sources are on average indistinguishable from those of the low-polarization sources. We conclude that the extraordinarily high average polarization must be due to intrinsic properties of the sources, such as an extremely ordered source magnetic field, low internal thermal plasma density or a preferential orientation of the source magnetic field perpendicular to the line of sight.
Testing the correlation between bending angle and polarization properties of bent radio galaxies
David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto（多伦多大学戴维·A·邓普尔天文学与天体物理系）；Dunlap Institute for Astronomy and Astrophysics, University of Toronto（多伦多大学邓普尔天文学与天体物理研究所）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；Department of Astronomy and Astrophysics, University of California, Santa Cruz（加州大学圣克鲁兹分校天文学与天体物理系）；Dominion Radio Astrophysical Observatory, Herzberg Astronomy and Astrophysics, National Research Council Canada（加拿大国家研究委员会赫茨伯格天文学与天体物理部 Dominion 射电天文观测站）
Radio Polarization Properties of Quasars and Active Galaxies at High Redshifts
我们提出了有史以来最大的样本的无线电偏振特性的$z>4$源，14个源具有显着的偏振检测。利用Karl G.利用Jansky甚大阵，我们获得了37个射电源的静止坐标系总强度和偏振特性，其中9个射电源的光谱红移在$1 \le z \le 1.4$范围内，另外28个射电源的光谱红移在$3.5 \le z \le 6.21$范围内。拟合斯托克斯$I$和分数偏振光谱，法拉第旋转措施得到使用旋转措施合成和$QU$拟合。利用476个偏振源的存档数据，我们比较了高红移（$z>3$）源的性质，一个$15\,$ GHz的静止帧亮度匹配样本的低红移（$z<3$）源，调查如果在高红移的无线电源的偏振特性是本质上不同于那些在低红移。我们发现一个平均值的旋转测量绝对值，校正银河系旋转，$50 \pm 22\,$ rad m $^{-2}$的$z>3$源和$57 \pm 4\,$ rad m $^{-2}$的$z<3$。虽然有一些迹象表明，较低的内在旋转措施，在高$z$可能是由于更高的去极化从高密度的环境，使用几个统计测试，我们发现没有显着差异，低和高红移源。需要更大的样本来确定任何真正的物理差异。
