Invited Talk - Plenary
4MOST and its science
Roelof de Jong
Leibniz-Institut für Astrophysik Potsdam (AIP)
I will present the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO’s four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view of 4.4 square degrees, a high multiplex fibre positioner based on the tilting spine principle positioning 2436 science fibres, 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20,000). 4MOST is nearing the completion of its construction phase and after an extensive test and verification phase in both Europe and on the telescope, start of full science operations is expected in early 2024. Next to detailing the instrument, I will give an overview of the science programme of 4MOST, both of the 4MOST Consortium Surveys and of the newly selected ESO Community Surveys. 4MOST is expected to deliver spectra for more than 30 million targets in its first 5-year survey for a very diverse range of science cases. The survey will cover a large part of the southern sky, complementing in particular large area space missions like Gaia, PLATO, eROSITA, and Euclid, and ground-based survey facilities like Rubin Observatory, VISTA, and SKA and its precursors. I will also present the carefully planned operations software for observing strategy planning, data analysis, and archiving/publication, needed for such a diverse science programme.