Milliarcsecond Polarization Studies of Compact ExtragalacticRadio Sources

AST 98-02708 John Wardle 沃德尔博士正在以最高的分辨率（秒差距或更小的线性尺度）研究强大的河外射电源。 他正在使用甚长基线阵列（VLBA）和协调毫米VLBI阵列。 这些河外射电源的能量来源是在类星体和活动星系的中心观测到的。 巨大的能量是在非常小的体积中产生的，尽管广泛地说是由于物质落入超大质量黑洞。 在无线电波段，人们可以看到紧凑的“核心”和细长的“喷流”，它们的总强度和偏振变化很快。 通常，明亮的无线电发射似乎以数倍于光速的速度沿着喷流向下移动。 PI正在以毫弧秒的分辨率对来自这些射电源的偏振（同步加速器）辐射进行成像。 线偏振图像包含关于磁场的顺序和方向以及相对论性像差的独特信息，这些信息不能从总强度图像中获得。 这些图像的序列形成了“磁场电影”的帧，其中磁场的演变可以在时间和空间上进行。 ***

AST 98-02708 John Wardle Dr. Wardle is studying powerful extragalactic radio sources at the highest resolution attainable (on a linear scale of parsecs or less). He is using the Very Long Baseline Array (VLBA) and the Coordinated Millimeter VLBI Array. The energy sources for these extragalactic radio sources are observed in the centers of quasars and active galaxies. Enormous amounts of energy are generated in very small volumes, widely though to be due to the infall of material onto a supermassive black hole. At radio wavelengths one sees compact 'cores' and elongated 'jets' that vary rapidly in total intensity and polarizataion. Often bright knots of radio emission appear to move down the jets at several times the speed of light. The PI is imaging the polarized (synchrotron) radiation from these radio sources at milliarcsecond resolution. Linearly polarized images contain unique information about the order and orientation of the magnetic field, and on relativistic aberration, that cannot be obtained from total intensity images. Sequences of such images form frames of the "magnetic movie" in which the evolution of the magnetic field can be followed in both time and space. ***