IRAM 30m Telescope

IRAM 30m Telescope
Name	IRAM 30m Telescope
Location	Pico Veleta, Sierra Nevada, Spain
Altitude	2850 m
Established	1984
Operator	Institut de Radioastronomie Millimétrique
Type	Single-dish radio telescope
Diameter	30 m

IRAM 30m Telescope The IRAM 30m Telescope is a millimetre-wavelength single-dish radio telescope located on Pico Veleta in the Sierra Nevada near Granada, Spain, operated by the Institut de Radioastronomie Millimétrique. It serves as a national and international facility used by astronomers from institutions such as the Max Planck Society, CNRS, and INSU, and it complements interferometers and observatories like the Atacama Large Millimeter/submillimeter Array, Plateau de Bure Interferometer, and the James Clerk Maxwell Telescope. The telescope supports studies ranging from molecular spectroscopy and star formation to active galactic nuclei and cosmology.

History

The project traces its institutional roots to collaborations involving the Centre National de la Recherche Scientifique and the Max-Planck-Institut für Radioastronomie during the 1970s and 1980s, contemporaneous with developments at observatories such as the National Radio Astronomy Observatory and the European Southern Observatory. Construction on Pico Veleta followed site surveys influenced by work at Mauna Kea and Chajnantor, and the facility began scientific operations in the mid-1980s, overlapping with upgrades at the Nobeyama Radio Observatory and the Submillimeter Array. Over decades the telescope has hosted programs connected to projects led by institutions like CNRS, MPG, the University of Granada, and national funding agencies such as the Deutsche Forschungsgemeinschaft and the Spanish Ministerio de Ciencia.

Site and Instrumentation

Situated at about 2850 metres elevation on Pico Veleta in the Sierra Nevada, the site offers dry atmospheric windows favorable for millimetre astronomy similar to sites chosen by the Atacama Pathfinder Experiment and the South Pole Telescope. The infrastructure includes dome and cable-way facilities coordinated with regional authorities in Andalusia and technical collaborations with firms engaged by the European Space Agency and the Instituto Geográfico Nacional. Instrumentation on-site is integrated with cryogenic systems developed in partnership with companies and laboratories affiliated with the Max Planck Society, CNRS, and Universidad de Granada, enabling receivers and calibration units comparable to systems used at the Institut de Radioastronomie Millimétrique headquarters in Grenoble.

Telescope Design and Optics

The 30-metre parabolic reflector employs a wheel-and-spoke backup structure with active surface adjustments inspired by engineering practices at the Green Bank Telescope and the Effelsberg 100-m Radio Telescope. Optical design incorporates Gregorian secondary optics and tertiary mirrors to feed heterodyne and bolometric receivers, following concepts deployed at the Nobeyama 45-m and the IRAM Plateau de Bure facilities. Surface accuracy and pointing systems use metrology techniques developed alongside instrumentation groups at the Technical University of Munich and the Observatoire de Paris, allowing operations across bands used by molecular line surveys and continuum mapping analogous to programs at the Caltech Submillimeter Observatory.

Receivers and Backends

The facility hosts a suite of heterodyne receivers covering bands in the 3 mm, 2 mm, and 1.3 mm windows, with multi-pixel and single-pixel configurations evolved from collaborative work with receivers at the James Clerk Maxwell Telescope and the Heinrich Hertz Submillimeter Telescope. Backends include autocorrelators and Fast Fourier Transform spectrometers similar to systems used at the Atacama Large Millimeter/submillimeter Array correlator development, enabling high spectral resolution studies akin to those pursued at the Very Large Array and the Australian Telescope National Facility. Cryogenic low-noise amplifiers and SIS mixers trace their heritage to developments at institutions such as the Jet Propulsion Laboratory and the Max Planck Institute for Radio Astronomy.

Observing Modes and Capabilities

Observing modes comprise position switching, beam switching, on-the-fly mapping, and frequency switching—modes that mirror operations at the Submillimeter Array and the Nobeyama Radio Observatory—supporting mapping projects comparing to surveys from the Herschel Space Observatory and the Planck mission. Capabilities include spectral-line surveys, continuum photometry, polarization measurements, and VLBI participation in campaigns coordinated with the Event Horizon Telescope and other networks including the European VLBI Network and Global mm-VLBI Array. Users from universities such as University of Cambridge, Harvard University, Universidad Complutense de Madrid, and institutions like CNRS and MPG regularly exploit these modes for Time Allocation Committee–approved programs.

Scientific Discoveries and Surveys

Science produced spans detections of complex organic molecules in star-forming regions, contributions to molecular inventories in sources studied also by the Spitzer Space Telescope and the Hubble Space Telescope, studies of protoplanetary disks related to work at the Very Large Array and ALMA, and surveys of nearby galaxies complementing data from the Sloan Digital Sky Survey and the Two Micron All Sky Survey. The telescope played roles in characterizing molecular gas in the Milky Way, in starburst galaxies like M82, in active galaxies such as NGC 1068, and in high-redshift quasars linked to surveys by the Submillimeter Common-User Bolometer Array and the South Pole Telescope. Results have been published in journals including Astronomy & Astrophysics, The Astrophysical Journal, and Monthly Notices of the Royal Astronomical Society, often in collaboration with teams from MIT, Caltech, the University of Tokyo, and the Instituto de Astrofísica de Canarias.

Operations, Management, and Upgrades

Operations are managed by the Institut de Radioastronomie Millimétrique under governance involving CNRS and the Max Planck Society, with support from national agencies in Spain and international partners such as the European Southern Observatory on technical issues. Management oversees user support, time allocation procedures, and technical upgrades including surface actuators, new heterodyne arrays, and digital backends paralleling upgrade paths at ALMA and the Karl G. Jansky Very Large Array. Future upgrade plans align with developments pursued by collaborators at institutions like the Centre for Astrophysics | Harvard & Smithsonian, the University of Bordeaux, and the Observatoire de Paris to maintain competitiveness in molecular astrophysics, VLBI, and time-domain millimetre astronomy.

Category:Radio telescopes Category:Millimetre astronomy Category:Observatories in Spain