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. ***
