a Telescopes without restrictions on access by U.S. astronomers.
b Approximately 30 to 50 percent of time available to U.S. community.
c To be decommissioned in 1991-1992.
in extragalactic surveys of HI in galaxies even after the Green Bank Telescope is built.
MILLIMETER AND SUBMILLIMETER WAVELENGTH ASTRONOMY
The focus of U.S. activity in millimeter and submillimeter astronomy (Table 3.2) shifted during the 1980s from single dishes to interferometers, beginning with the inauguration of millimeter interferometers at Owens Valley (Caltech) and Hat Creek (Berkeley, University of Illinois, and the University of Maryland). These small arrays of 6- to 10-m telescopes have made important contributions to many fields of galactic and extragalactic astronomy. Important results include, for example, the discovery of molecular gas concentrated at the center of infrared-luminous galaxies and the imaging of protoplanetary disks associated with young stars.
Submillimeter astronomy is expected to become a major field of research in the 1990s. The Caltech Submillimeter Observatory began operations in 1990 with significant support from the NSF and with 50 percent of the observing time available to the national community. This telescope, a small program recommended by the Field Committee, has taken advantage of sensitive receivers and clever telescope fabrication techniques to pioneer observations in