Llano de Chajnantor Observatory

Llano de Chajnantor Observatory is a world-renowned astronomical facility located on a high-altitude plateau in the Andes mountains of northern Chile. It is one of the premier sites on Earth for submillimeter astronomy and millimeter-wave astronomy, hosting several major international telescope arrays. The extreme dryness and atmospheric stability of its location make it uniquely suited for observing the universe at wavelengths that are typically absorbed by water vapor in the Earth's atmosphere.

Location and environment

The observatory is situated on the Llano de Chajnantor plateau within the Atacama Desert, approximately 50 kilometers east of San Pedro de Atacama in the Antofagasta Region. This region is famed as one of the driest places on Earth, with exceptionally low precipitation and minimal atmospheric water vapor. The site's elevation of approximately 5,000 meters (16,400 feet) above sea level places it above a significant portion of the Earth's atmosphere, further reducing interference for sensitive astronomical observations. The Chajnantor plateau is administered by the Atacama Large Millimeter Array (ALMA) and shares its exceptional conditions with other nearby facilities like the Atacama Pathfinder Experiment (APEX) telescope and the University of Tokyo Atacama Observatory (TAO).

Major telescopes and instruments

The flagship instrument at the site is the Atacama Large Millimeter/submillimeter Array (ALMA), an international partnership between Europe, North America, and East Asia in cooperation with the Republic of Chile. ALMA consists of 66 high-precision antennas that work together as a single, powerful interferometer. Other significant instruments include the Atacama Pathfinder Experiment (APEX), a single-dish telescope modified from a prototype ALMA antenna, and the POLARBEAR experiment, which studies the cosmic microwave background. The Chilean National Telescope (TNC) and the NANTEN2 Observatory have also conducted important surveys from this location.

Scientific research and discoveries

Research at the observatory has profoundly advanced our understanding of the cold universe, probing regions obscured by cosmic dust. Key discoveries include detailed imaging of protoplanetary disks around young stars like HL Tauri, revealing the early stages of planet formation. Observations have mapped the distribution of cold molecular gas in nearby galaxies such as the Andromeda Galaxy and Centaurus A, and have studied the star formation processes in the Milky Way. Instruments like ALMA have also been crucial in detecting complex organic molecules in interstellar space and in studying the properties of the cosmic microwave background radiation, providing insights into the Big Bang and the evolution of the cosmos.

History and development

The site's potential for millimeter-wave astronomy was identified in the 1990s through extensive site-testing campaigns led by organizations including the National Radio Astronomy Observatory (NRAO) and the European Southern Observatory (ESO). Formal development began in 1999, and the Atacama Large Millimeter Array project was approved in 2003. Construction of the massive ALMA array, a collaboration between the National Science Foundation (NSF), ESO, and the National Institutes of Natural Sciences, Japan (NINS), took place throughout the 2000s, with early science observations starting in 2011. The official inauguration of the completed ALMA observatory was held in March 2013.

Collaborations and institutions

The observatory is a hub of global scientific cooperation. ALMA is a partnership of the European Southern Observatory (ESO), representing its member states, the National Science Foundation (NSF) in the United States, and the National Institutes of Natural Sciences (NINS) in Japan, in cooperation with the Republic of Chile. The Atacama Pathfinder Experiment telescope is operated by the Max Planck Institute for Radio Astronomy (MPIfR) in collaboration with ESO and the Onsala Space Observatory. Numerous other universities and research institutes from around the world, including the University of Chile and the University of Tokyo, participate in observations and instrument development at the site.

Category:Astronomical observatories in Chile Category:Radio telescopes