The optical/infrared astronomical quality of high Atacama sites. II. Infrared characteristics

Citation
R. Giovanelli et al., The optical/infrared astronomical quality of high Atacama sites. II. Infrared characteristics, PUB AST S P, 113(785), 2001, pp. 803-813
Citations number
10
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
0004-6280 → ACNP
Volume
113
Issue
785
Year of publication
2001
Pages
803 - 813
Database
ISI
SICI code
0004-6280(200107)113:785<803:TOAQOH>2.0.ZU;2-7
Abstract
We discuss properties of the atmospheric water vapor above the high Andean plateau region known as the Llano de Chajnantor, in the Atacama Desert of n orthern Chile. A combination of radiometric and radiosonde measurements ind icates that the median column of precipitable water vapor (PWV) above the p lateau at an elevation of 5000 m is approximately 1.2 mm. The exponential s cale height of the water vapor density in the median Chajnantor atmosphere is 1.13 km; the median PWV is 0.5 mm above an elevation of 5750 m. Both of these values appear to be lower at night. Annual, diurnal, and other depend ences of PWV and its scale height are discussed, as well as the occurrence of temperature inversion layers below the elevation of peaks surrounding th e plateau. We estimate the background for infrared observations and sensiti vities for broadband and high-resolution spectroscopy. The results suggest that exceptional atmospheric conditions are present in the region, yielding high infrared transparency and high sensitivity for future ground-based in frared telescopes.