4MOST - 4-metre Multi-Object Spectroscopic Telescope
4-m Multi-Object Spectroscopic Telescope
4MOST

Overview

The 4MOST consortium has been selected by the European Southern Observatory (ESO) to provide the ESO community with a fibre-fed spectroscopic survey facility on the VISTA telescope with a large enough field-of-view to survey a large fracĀ­tion of the southern sky in a few years.Ā The facility will be able to simultaneously obtain spectra of ~2400 objects distributed over an hexagonal field-of-view of 4.2 square degrees. This high multiplex of 4MOST, combined with its high spectral resolution, will enable detection of chemical and kinematic substructure in the stellar halo, bulge and thin and thick discs of the Milky Way, thus help unravel the origin of our home galaxy. The instrument will also have enough wavelength coverage to secure velocities of extra-galactic objects over a large range in redĀ­shift, thus enabling measurements of the evolution of galaxies, black holes, and the structure of the cosmos.

This exceptional instrument enables many science goals, but the design is especially intended to complement three key allĀ­-sky, spaceĀ­-based obĀ­servatories of prime European interest: Gaia, Euclid, and eROSITA. Such a facility has been identified as of critical importance in numerous European strategic documents (Bode et al., 2008; de Zeeuw & Molster 2007; Drew et al. 2010; Turon et al. 2008) and forms the perfect comĀ­plement to the many allĀ­-sky survey proĀ­jects around the world.

4MOST is currently in its Manufacturing, Assembly, Integration and TestĀ Phase with an expected start of full science operations in Q1 2024.


Science

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4MOST enables many science goals, but its design in particular complements a number of key large-area, spaceĀ­-based observatories of prime European interest: Gaia, eROSITA, Euclid, and PLATO, and future ground-based, wide-area survey facilities like the Vera C. Rubin Observatory and SKA. 4MOST will unfold maximum impact by operating continuously for an initial five-year Public Survey programme delivering spectra for ā‰„25 million objects over ā‰„15 000 square degrees.

The first five-year survey of 4MOST consists of 10 Programmes developed by the Consortium and 15 Programmes from the ESO community. Read more about 4MOST science and the survey programme.

Facility

The 4MOST Facility comprises the instrument as well as the software to schedule and observe many surveys in parallel, and the data management system to reduce, analyse, validate and publish all data, including higher-level data products (radial velocities/redshifts, stellar parameters, abundances, etc.).

Find out more about the facility.

Consortium

The 4MOST consortium consists of 15 institutes in Germany, Australia, France,Ā the Netherlands, Sweden, Switzerland, and the UK,Ā under leadership of the Leibniz-Institut fĆ¼r Astrophysik Potsdam (AIP).

See all consortium partners and their roles.