The National Radio Astronomy Observatory (NRAO) conceives, designs, builds, operates, and maintains world-class radio telescopes used by scientists from around the world to study virtually all types of astronomical objects, from bodies in our own Solar System to galaxies in the distant Universe. The NRAO facilities currently include the international Atacama Large Millimeter/submillimeter Array (ALMA) located in Chile; the Karl G. Jansky Very Large Array (VLA) located near Socorro, New Mexico; and the Very Long Baseline Array (VLBA), with antennas at ten sites in Hawai’i, St. Croix, and across the continental United States. NRAO, located in Charlottesville, Virginia, also operates a Central Development Laboratory (CDL) in Charlottesville providing technology and expertise in supporting current and future radio astronomy instrumentation.
ALMA enables transformational research into the physics of the cold Universe, regions that are optically dark but shine brightly in the millimeter/submillimeter portion of the electromagnetic spectrum. ALMA provides one to two orders of magnitude improvement over previous facilities in all areas of millimeter- and submillimeter-wave observations, including sensitivity, angular resolution and image fidelity. ALMA is a general-purpose facility that started operation in 2011, overlapping with construction which was completed in 2015. Within the broad range of science accessible with ALMA, the top-level objectives include imaging the redshifted dust continuum and molecular line emission from evolving galaxies in the early Universe, determining the chemical composition and dynamics of star-forming gas in nearby and distant, but normal, galaxies like the Milky Way, and measuring the gas kinematics in young disks in nearby molecular clouds and detecting the tidal gaps induced by planet formation.
The VLA is the world’s leading centimeter-wavelength radio telescope. Following a major overhaul completed in early 2013, the VLA provides one to three orders of magnitude improvement over all previous performance aspects except angular resolution. Among a broad range of scientific capabilities, the VLA addresses four primary science themes: measuring the strength and topology of cosmic magnetic fields; imaging young stars and massive black holes in dust-enshrouded environments; following the rapid evolution of energetic phenomena; and studying the formation and evolution of stars, galaxies and active galactic nuclei.
The VLBA provides the astronomical community users with a unique and fully dedicated facility able to conduct sensitivity-limited radio observations with an astrometric precision as high as 5 microarcsec, over the frequency range of 0.3 to 96 GHz. It is the only Very Long Baseline Interferometry (VLBI) facility in the world with availability and responsiveness for observing transient events in an efficient and timely way. With the VLBA, astronomers can conduct observations from the smallest physical scales such as the surfaces of asteroids, penetrate through the dusty disk of the Milky Way to observe star forming regions beyond the Galactic Center, measure the distances to pulsars and monitor pairs of super-massive black holes billions of light-years away.
As a national facility, NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO carries out a vigorous program in education for public visitors to its facilities, undergraduates interested in astronomy, graduate students conducting dissertation research in astronomy, and postdoctoral researchers desiring access to its facilities.
NRAO operations and management are supported under the terms of a cooperative agreement between NSF and Associated Universities, Inc. (AUI), a 'not-for-profit' science management corporation. ALMA is an international partnership of NSF, ESO (representing its member states), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile.