Milliarcsecond Polarization Studies of Compact ExtragalacticRadio Sources

利用甚长基线干涉测量(VLBI)技术，将研究紧凑型射电源发射的射电波长的线偏振分布。这些射电源与类星体和活动星系的核有关，在这些星系中，巨大的能量以非常短的时间尺度发射，可能是由于物质流入超大质量黑洞。这种能量在电磁光谱的所有部分都表现为辐射。在无线电波长上，我们看到紧凑的无线电发射“核心”和“喷气式”特征，总强度和偏振变化很快。在许多源中，明亮的放射物似乎正以几倍于光速的速度沿着喷流而下。观测的目的是：(1)绘制磁场结构的拓扑图并研究它们的演化；(2)获得运动学和几何信息以建立超光速源的模型；(3)帮助理解不同类别的致密射电源之间的差异；(4)探测类星体和活动星系核最内部区域RDIO源周围的等离子体；(5)研究毫角秒射电结构与扩展射电源中发现的大尺度(远大于1角秒)喷流和波瓣之间的关系。

The distributions of the linear polarization of radio wavelength emission from compact radio sources will be studied at milliarcsecond resolution using the technique of the Very Long Baseline Interferometry (VLBI). These radio sources are associated with the nuclei of quasars and active galaxies, where enormous amounts of energy are emitted on very short timescales, probably due to the infall of material onto a supermassive black hole. The energy manifests itself as radiation on all parts of the electromagnetic spectrum. At radio wavelengths we see compact radio-emitting `cores' and `jet-like' features, that vary rapidly in both total intensity and polarization. In many sources, bright knots of emission appear to be moving down the jets at several times the speed of light. The goals of the observations are: (1), to map the topology of the magnetic field structures and to study their evoulution; (2), to obtain kinematic and geometric information to constrin models of superluminal sources; (3), to help understand the differences between differnt classes of compact radio sources; (4), to probe the plasma surrounding the rdio sources in the innermost regions of quasars and active galactic nuclei; and (5), to study the relationship between the milliarcsecond radio structure and the large scale (much greater than 1 arcsecond) jets and lobes found in extended radio sources.