This grant supports a study of small, compact features in quasars and other active galactic nuclei through a series of multi- frequency observations extending from the radio to gamma-ray emissions. This research will increase our understanding of the mechanisms that govern quasars, the most distant and energetic power sources in the universe. The grant also supports monitoring of nearby clouds of molecular gas to search for variability in their brightness at certain wavelengths that is expected as the interstellar medium of our own Galaxy moves between us and background sources of radio emission. This study will increase our understanding of the content, structure and distribution of the gas in the Milky Way. This work, led by Drs. Alan Marscher and Thomas Bania of Boston University builds the educational and research infrastructure of astronomy by training new scientists in the technical skills needed to effectively use the new VLBA (Very Long Baseline Array), which is now near completion.
