Unwin, Stephen; Wehrle, Ann; Meier, David; Jones, Dayton; Piner, Glenn
(Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2007., 2007-10-15)
Optical astrometry of quasars and active galaxies can provide key information on the spatial distribution and variability of emission in compact nuclei. The Space Interferometry Mission (SIM PlanetQuest) will have the ...