Northern Extended Millimeter Array

Northern Extended Millimeter Array. It is a powerful radio interferometer located at the Institut de Radioastronomie Millimétrique's site on the Plateau de Bure in the French Alps. As a major enhancement of the original Plateau de Bure Interferometer, it is designed for high-resolution observations in the millimeter and submillimeter regimes. The facility is a cornerstone instrument for studying the cold universe, including the formation of stars and planets, and the dynamics of distant galaxies.

Overview

The array was inaugurated in 2014 following a significant upgrade project led by the Institut de Radioastronomie Millimétrique in partnership with several European research agencies. It is situated at an altitude of 2,550 meters on the Plateau de Bure, a location chosen for its exceptional atmospheric stability and dryness, which are critical for millimeter-wave observations. The primary scientific goal is to probe cosmic structures obscured by interstellar dust, such as nascent stellar nurseries within the Milky Way and the gaseous reservoirs of high-redshift galaxies. Its work is complementary to other major international facilities like the Atacama Large Millimeter Array in Chile and the Submillimeter Array on Mauna Kea.

Technical specifications

The interferometer consists of ten antennas, each 15 meters in diameter, made from high-precision carbon fiber to ensure surface accuracy under varying thermal conditions. These antennas can be reconfigured along several rail tracks, providing a maximum baseline of approximately 760 meters, which yields an angular resolution finer than 0.5 arcseconds at its highest frequencies. It operates across a wide range of frequencies, from about 80 to 350 GHz, covering important molecular and atomic transition lines from species like carbon monoxide and water vapor. The array's correlator, named the WideX backend, allows for instantaneous broadband spectroscopy, which is vital for detecting complex organic molecules in regions like the Orion Nebula.

Scientific contributions

Key discoveries include detailed imaging of the protoplanetary disks around young stars such as HL Tauri, revealing gaps and structures indicative of ongoing planet formation. The array has mapped the distribution of molecular clouds and turbulent gas flows in nearby galaxies like the Andromeda Galaxy and the Triangulum Galaxy. In extragalactic astronomy, it has been instrumental in studying the star formation history and interstellar medium conditions in dusty starburst galaxies discovered by missions like the Herschel Space Observatory. Observations of objects like the quasar APM 08279+5255 have provided constraints on fundamental physics, including potential variations in the fine-structure constant.

Collaboration and governance

The facility is operated and maintained by the Institut de Radioastronomie Millimétrique, a French-German-Spanish partnership supported by the Centre National de la Recherche Scientifique, the Max Planck Society, and the Instituto Geográfico Nacional. Observing time is allocated through competitive peer-review proposals submitted by the international scientific community, with significant programs often involving collaborations with institutes like the European Southern Observatory and NASA. Data from the array are archived and distributed through the IRAM Science Data Center, supporting legacy research projects. Its operations are coordinated with the global Event Horizon Telescope network for very-long-baseline interferometry campaigns.

See also

* Atacama Large Millimeter Array * Submillimeter Array * James Clerk Maxwell Telescope * Green Bank Telescope * Very Large Array * Millimeter astronomy

Category:Radio telescopes Category:Astronomical observatories in France Category:Millimeter-wave telescopes