Back to Volume
Paper: ALMA: Exploring the Outer Limits of the Millimeter Sky
Volume: 356, Revealing the Molecular Universe: One Antenna Is Never Enough
Page: 59
Authors: Wootten, A.
Abstract: The Atacama Large Millimeter Array (ALMA1) is a billion-dollar, international telescope project under construction in northern Chile on a 5-km elevation site at Chajnantor. The excellent atmospheric transmission in the millimeter and sub-millimeter wavelength ranges at that site will allow ALMA to provide detailed images of the sources of the cosmic microwave background and the cosmic far-infrared background radiation near the wavelengths of the two strongest peaks in the spectral energy distribution of the Universe. ALMA's images will contain all of the flux in the imaged field through the use of two parts: (1) the “12-m Array,” composed of up to sixty-four 12-m antennas that can be placed on 186 different stations for baselines up to 18 km; and (2) the “Atacama Compact Array,” or ACA, that consists of twelve 7-m telescopes placed in compact configurations and four 12-m telescopes for measuring source total power. The angular resolution will be 0.00500 at the shortest planned wavelength of 0.3mm and on the longest baseline. The receivers use superconducting (SIS) mixers that, in combination with the excellent site transparency and the large collecting area, will provide sensitivity at 1mm wavelength of 1 mJy in a few seconds for average atmospheric conditions. This sensitivity is more than two orders of magnitude better than any array operating today. At first light for the ALMA project, the 6 highest priority receiver bands will be installed, each observing both polarizations with bandwidths of 8 GHz.
Back to Volume