15个活动星系核的高频多波段偏振观测：相关偏振行为
Multiwaveband Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Correlated Polarization Behavior
摘要：
本文报道了对15个含有高度相对论喷流的活动星系核的多频线偏振监测，这些喷流的视速度从$\sim$ 4 $c$到$>40c$。在光学、1 mm和3 mm波长处以及在7 mm处使用甚长基线阵列获得测量值。数据显示，在源之间的线性偏振度的范围很广，从$<$ 1%到$>$ 30%，以及在个别源的日间偏振变化。偏振特性表明，样品分为三组，在7 mm处的岩心中具有低、中和高偏振变化性：分别为LVP、IVP和HVP。这些星系群部分与活动星系核的共同分类有关，如射电星系和低光学偏振类星体（LVP），BL Lacertae天体（IVP）和高光学偏振类星体（HVP）。我们的研究调查之间的相关性总通量，分数偏振，偏振位置角在不同的波长。我们通过弱激波压缩射流中湍流等离子体的模型解释了样品中源的偏振特性。源相对于观测者的取向、喷流运动学和喷流外部靠近核心的热物质丰度的差异可以解释偏振特性的多样性。结果提供了强有力的证据，光学偏振发射起源于冲击，最有可能位于3毫米和7毫米VLBI核心之间。他们还支持的想法，1毫米的核心在于之间的过渡区的边缘的电磁主导和湍流流体动力学部分的射流。
英文摘要：
We report on multi-frequency linear polarization monitoring of 15 active galactic nuclei containing highly relativistic jets with apparent speeds from $\sim$4 $c$ to $>40c$. The measurements were obtained at optical, 1 mm, and 3 mm wavelengths, and at 7 mm with the Very Long Baseline Array. The data show a wide range in degree of linear polarization among the sources, from $<$1% to $>$30%, and interday polarization variability in individual sources. The polarization properties suggest separation of the sample into three groups with low, intermediate, and high variability of polarization in the core at 7 mm : LVP, IVP, and HVP, respectively. The groups are partially associated with the common classification of active galactic nuclei as radio galaxies and quasars with low optical polarization (LVP), BL Lacertae objects (IVP), and highly optically polarized quasars (HVP). Our study investigates correlations between total flux, fractional polarization, and polarization position angle at the different wavelengths. We interpret the polarization properties of the sources in the sample through models in which weak shocks compress turbulent plasma in the jet. The differences in the orientation of sources with respect to the observer, jet kinematics, and abundance of thermal matter external to the jet near the core can account for the diversity in the polarization properties. The results provide strong evidence that the optical polarized emission originates in shocks, most likely situated between the 3 mm and 7 mm VLBI cores. They also support the idea that the 1 mm core lies at the edge of the transition zone between electromagnetically dominated and turbulent hydrodynamical sections of the jet.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
