Milliarcsecond Polarization Studies of Compact ExtragalacticRadio Sources

02708约翰·沃德博士正在研究强大的河外射电源，分辨率达到最高(以秒为单位的线性尺度)。他正在使用甚长基线阵列(VLBA)和协调的毫米波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察到的。巨大的能量是在非常小的体积内产生的，虽然广泛地说是由于物质流入超大质量黑洞。在射电波段，人们可以看到致密的“核心”和细长的“喷流”，它们的总强度和偏振变化很快。通常，明亮的射电发射结似乎以几倍于光速的速度沿着喷流移动。PI正在以毫角秒的分辨率成像来自这些射电源的极化(同步辐射)辐射。线偏振图像包含有关磁场的顺序和方向以及相对论像差的独特信息，这是从总强度图像中无法获得的。这样的图像序列形成了可以在时间和空间上跟踪磁场演变的“磁性电影”的帧。***

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. ***