Over the past three years the Combined Array for Research in Millimeter Astronomy (CARMA) was formed from the merger of two telescope arrays supported by the Division of Astronomical Science's University Radio Observatories (URO) Program, these being Caltech?s Owens Valley Radio Observatory (OVRO) array of six 10.4-meter-diameter telescopes, and the Berkeley Illinois Maryland Association (BIMA) array of nine 6.1-meter-diameter telescopes. With commissioning at the new site now complete, CARMA will achieve resolutions as high as 0.2 arcseconds at a wavelength of 1mm and, due to its heterogeneous combination of telescope diameters, will provide excellent imaging over a wide range of angular scales. When new receivers are installed in 2009, CARMA's sensitivity in the 1 mm band will be an order of magnitude greater than that of the previous arrays. The new science enabled by CARMA covers a broad range of astronomical topics, including star formation and molecular clouds, studies of external galaxies, and the investigation of solar system objects. CARMA is a pathfinder for the Atacama Large Millimeter Array (ALMA) and a pipeline for training experts in the field of millimeter interferometry to take full advantage of ALMA's capabilities for US astronomy.
CARMA (the Combined Array for Research in Radio Astronomy) is an array of 23 radio telescopes located in the Inyo Mountains near Big Pine, CA. The telescopes are electronically linked together as an "aperture synthesis telescope" to produce images of the astronomical sky at wavelengths of 10-mm, 3-mm, and 1.3-mm. The array is managed by a consortium of universities - Caltech, U.C. Berkeley, Illinois, Maryland, and Chicago - and the telescopes are operated by students from these and other institutions. A significant fraction of the observing time supports student PhD projects. Many of the radio signals of interest are emitted at very specific frequencies by trace molecules (carbon monoxide, hydrogen cyanide, methanol, and many others) inside cold clouds of molecular hydrogen in interstellar space. From these radio signals astronomers can measure the velocity of the gas along the line of sight, allowing studies of the infall of material onto new stars or the rotation of galaxies. Other radio signals originate from dust grains inside these clouds, from hot gas around young stars, or from the cosmic microwave background radiation. Some examples of recent discoveries made with CARMA: Black hole mass. The orbital velocities of molecular gas at the center of the lenticular galaxy NGC 4526, 50 million light years away, show that a supermassive black hole lurks at its center. The black hole has 450 million times the mass of the Sun. This is the first time that a black hole mass has been determined from the motions of molecular gas, and is one of the most precise measurements of a black hole mass to date (Davis et al. 2013, Nature, 494, 328). Galaxy mergers. Observations of radio emission from carbon monoxide molecules in elliptical and lenticular galaxies demonstrates that in many cases these galaxies have recently swallowed smaller spiral galaxies (Alatalo et al. 2013, Monthly Notices of the Royal Astronomical Society, 432, 1796). Circumstellar disks. Radio waves emitted by interstellar dust grains show that magnetic fields near newborn stars tend to be misaligned with the planet-forming disks that surround these stars. This result hints that magnetic fields inhibit the formation of such disks (Hull et al. 2013, The Astrophysical Journal, 768, 159). Black hole spin. Some black holes launch powerful collimated jets of relativistic particles that extend outwards for hundreds or thousands of light years. Coordinated observations between CARMA and other radio telescopes in Hawaii and Arizona showed that the jet in the galaxy M87 originates from a spot only 40 microarcseconds in diameter - the apparent size of a poppy seed viewed from a distance of 3000 miles. This measurement suggests that the jet originates from gas close to the innermost stable circular orbit around the central black hole, and that the black hole and disk are spinning in the same direction (Doeleman et al. 2012, Science, 338, 355). Neptune's atmosphere. Neptune has a high abundance of carbon monoxide in its upper atmosphere. The oxygen necessary for the formation of this CO may have originated from cometary impacts (Luszcz-Cook and de Pater 2012, Icarus, 222, 379).
