ABSTRACT AST-9420460. Rogers, Alan E. Millimeter-wavelength very long baseline interferometry (VLBI) achieves the highest angular resolution in astronomy--typically 50 microarcseconds at 3mm and 20 microarcseconds at 1mm. Only such resolutions can begin to reveal the compact astrophysical structures associated with the massive central engines of active galactic nuclei such as quasars and BL Lacertids, and only at millimeter wavelengths does one minimize the inherent limitations of continuum VLBI due to scattering by the interstellar plasma and optical depth effects. The millimeter band is also rich in molecular masers whose structure can only be resolved by VLBI. This three year award will provide support to form and operate a "Coordinated mm-VLBI Array" (CMVA). Replacing previous ad-hoc efforts in this field by a the unified scheduling, support and analysis infrastructure, the CMVA will make mm-wave VLBI available to all astronomers, not just those who are experts in the technique. The CMVA will consist of a core group of mm-wave observatories who have agreed to make approximately two weeks per year available for VLBI; an additional group of facilities will make time available on a per-proposal basis. The CMVA will be managed out of the Haystack Observatory. which is also one of the CMVA's core institutions. Haystack will coordinate the solicitation and review of mm-wave VLBI proposals from the astronomical community, and will coordinate scheduling, hardware and tape allocation, as well as in absentia data correlation; it will also provide the technical support necessary to make the CMVA reliable and fully functional, will loan two data acquisition systems to various CMVA sites, and will continue to develop advanced VLBI instrumentation. ***
