HARMONI

HARMONI
Name	HARMONI
Instrument type	Integral field spectrograph
Wavelength range	Visible to near-infrared
Location	Cerro Armazones, Atacama Desert, Chile
Built	UK-led consortium
First light	Planned for 2028

HARMONI. The High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph is a first-light instrument for the Extremely Large Telescope under construction in Chile. This powerful integral field spectrograph will provide simultaneous spatial and spectral data across a wide wavelength range, enabling unprecedented studies of the formation and evolution of cosmic structures. Its design is led by a consortium from the University of Oxford and involves major contributions from institutions across the United Kingdom, France, and Spain.

Overview

As a core first-light instrument, HARMONI is engineered to exploit the immense light-gathering power and spatial resolution of the Extremely Large Telescope. It will operate across the visible spectrum and near-infrared bands, from 0.47 to 2.45 micrometers, capturing detailed spectra for every pixel in its field of view. The instrument is designed to tackle key questions in modern astrophysics, including the assembly of the first galaxies and the dynamics of stars near the supermassive black hole at the center of the Milky Way. Its development is managed by a consortium including the UK Astronomy Technology Centre and the Laboratoire d'Astrophysique de Marseille.

Instrument design

The optical design of HARMONI is a complex, modular system featuring four separate spectrograph channels to cover its broad wavelength range efficiently. It employs advanced adaptive optics systems, including a single-conjugate mode using a laser guide star and a powerful natural guide star mode, to correct for atmospheric turbulence and achieve diffraction-limited performance. Key components include a monolithic image slicer to divide the field, state-of-the-art VPH gratings for dispersion, and large-format detectors from companies like Teledyne Imaging Sensors. The cryogenic and vacuum systems are engineered by teams at the Universidad Politécnica de Madrid.

Scientific capabilities

HARMONI's integral field unit will provide spatially resolved spectroscopy, enabling the mapping of gas kinematics in high-redshift galaxies to understand their rotation and merger histories. It will probe the stellar populations and interstellar medium in nearby galaxies like Andromeda with exceptional detail. The instrument is uniquely suited for studying exoplanet atmospheres through direct spectroscopy and will conduct deep surveys of the early universe, looking for signatures of the first stars and galaxies that emerged after the Big Bang. Observations of the Galactic Center will test predictions of general relativity near Sagittarius A*.

Development and construction

The HARMONI project is spearheaded by the University of Oxford Department of Physics, with the project office located at the UK Astronomy Technology Centre in Edinburgh. Major sub-system contributions come from partners like the Centre de Recherche Astrophysique de Lyon, the Instituto de Astrofísica de Canarias, and the Durham University Centre for Advanced Instrumentation. Assembly, integration, and testing phases are coordinated across facilities in the United Kingdom and at the European Southern Observatory headquarters in Garching bei München, Germany, before shipment to the telescope site in Chile.

Integration with the Extremely Large Telescope

HARMONI will be installed at the Nasmyth platform of the Extremely Large Telescope, interfacing directly with its complex adaptive optics modules and the telescope's massive primary mirror. Its operation will be synchronized with the telescope's control software developed by the European Southern Observatory. The instrument will work in concert with other first-light instruments like METIS and MICADO, allowing for complementary multi-wavelength studies. Data pipelines developed by institutes such as the University of Cambridge will process the immense data flow for distribution to the global astronomical community.

Expected scientific impact

HARMONI is anticipated to revolutionize our understanding of galaxy formation by providing the first detailed kinematic maps of galaxies in the early universe, shedding light on the effects of dark matter and dark energy. It will directly image and characterize exoplanetary systems around stars like Proxima Centauri. Observations will also refine the Hubble constant by measuring precise distances to celestial objects, contributing to cosmology. The instrument will support numerous legacy surveys, with data archived at facilities like the European Space Agency's European Space Astronomy Centre, ensuring a lasting impact for decades.

Category:Astronomical instruments Category:Extremely Large Telescope