An Etymological Dictionary of Astronomy and Astrophysics
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One of the largest ground-based astronomy projects and a major new facility for world astronomy located on the plain of the → Chajnantor Chilean Andes, San Pedro de Atacama, some 5000 m above sea level. ALMA will initially comprise 66 high precision antennas, with the option to expand in the future. There will be an array of fifty 12 m antennas, acting together as an → interferometer to capture → millimeter and → submillimeter wavelengths of 0.3 to 9.6 mm. It will have reconfigurable baselines ranging from 15 m to 18 km. A compact array of 7 m antenna and few 12 m diameter antennas (ACA) will be used to measure the diffuse emission. Resolutions as fine as 0''.005 will be achieved at the highest frequencies. Construction of ALMA started in 2003 and will be completed in 2012. The ALMA project is an international collaboration between Europe, Japan, and North America in cooperation with the Republic of Chile. ALMA is funded in Europe by the → European Southern Observatory (ESO). The first 12 m diameter antenna, built by Mitsubishi Electric Corporation for the National Astronomical Observatory of Japan, was handed over to ESO in 2008. It will shortly be joined by North American and European antennas. ALMA will allow astronomers to study the cool Universe, i.e. the molecular gas and tiny dust grains from which stars, planetary systems, galaxies, and even life are formed.

Atacama the name of a desert, west of the Andes mountains in Chile, covering a 1,000 km strip of land on the Pacific coast of South America; → large; → millimeter; → submillimeter; → array.

A retrograde irregular satellite of Neptune discovered in 2002. Also called Neptune IX. Halimede is about 62 kilometres in diameter.

In Gk. mythology, one of the Nereids, the fifty daughters of Nereus and Doris.

A white or grayish-white substance obtained by burning → limestone, used in mortars, plasters, cements, and in the manufacture of steel, paper, glass, and various chemicals of calcium.

M.E., O.E. lim; akin to Du. lijm, Ger. Leim, O.N. lim "glue;" L. limus "slime."

Âhak, probably a variant of xâk, → soil.

A → sedimentary rock composed principally of calcium carbonate. Limestone is usually formed from shells of once-living organisms or other organic processes, but may also form by inorganic precipitation.

→ lime; → stone.

Microwaves with wavelengths between 1 and 10 millimeter, corresponding to frequencies between 300 GHz to 30 GHz. → millimeter-wave astronomy.

→ milli-; → meter; → wave.

That part of radio astronomy which uses electromagnetic waves in the range 1-10 millimeter to study various components of the Universe, in particular the chemistry of interstellar matter.

→ millimeter wave; → astronomy.

Of or pertaining to scales smaller than millimeter.

→ sub-; → millimeter.

The study of astronomical objects with → submillimeter waves. As with millimeter-wave astronomy, this part of the spectrum is rich in lines emitted by interstellar molecules and dust.

→ submillimeter; → astronomy.

A member of an extremely luminous population of → high-redshift galaxies which are detected in → submillimeter waves (→ flux density at 850 μm ≥ 3 - 5 mJy). SMGs are powered primarily by star formation rather than an → active galactic nucleus (AGN). Because of their high → dust content, these galaxies emit almost all of their luminosity in the infrared, with a → bolometric luminosity ranging from 10¹²-10¹³ → solar luminosities. As such, SMGs resemble → ultraluminous infrared galaxies (ULIRGs), which are almost exclusively → merging galaxies. Indeed, many observations support a → merger origin for SMGs (see, e.g. C.C. Hayward et al. 2011 and references therein, astro-ph/1101.0002).

→ submillimeter; → galaxy.

That part of the → electromagnetic radiation with a → wavelength beyond 300 → microns.

→ submillimeter; → radiation.

An electromagnetic wave having wavelengths less than one millimeter (frequencies greater than 300 gigahertz).

→ millimeter; → wave.