Abstract

Invited Talk - Plenary

Thursday, 18 September 2025, 10:10   (Synagoge - Kuppelsaal / virtual plenum)

WST: the wide-field spectroscopic telescope

Matthias Steinmetz
Leibniz-Institut für Astrophysik Potsdam (AIP)

The Wide-Field Spectroscopic Telescope (WST) is a conceptual study of an innovative spectroscopic facility to be proposed as the next European Southern Observatory (ESO) infrastructure after completion of the 39-metre ELT. In 2030+, WST will prove crucial to answering key questions of astrophysics such as:
• Is the accelerated expansion of the Universe due to an unknown form of energy or to a modification of General Relativity on large scales?
• What is the interplay between dark, stellar, and gaseous material in galaxies and how does primordial and metal-enriched gas flow in and out of galaxies at various scales?
• What is the detailed formation history of our own Galaxy and of its satellites?
• What is the origin of many chemical elements that are crucial to trace Galactic evolution?
• What are the conditions that drive the formation and evolution of extra-solar planets?
• What are the extreme physical conditions that govern transient events (explosions, eruptions, and disruptions)?
WST is foreseen to employ a dedicated 12m telescope for wide-field spectroscopy simultaneously operating a large field-of-view (3 sq. degree) and high multiplex (20 000) multi-object spectrograph (MOS), including both low (LR) and high resolution (HR), and a giant panoramic central integral field unit (IFS). Top-level requirements include (i) a telescope diameter of 12m, (ii) a telescope field of view of 3.1 sqdeg, (iii) MOS spectral resolution R=3000-4000 (LR) and R~40000 (HR), (iv) MOS multiplex of 30000 (LR) and 2000 (HR), (v) a MOS spectral range of 370-970nm (LR) and 3-4 HR regions in the 350-970nm spectral range, (vi) an IFS field of view of 3x3 sqarcmin, (vii) an IFS spectral resolution R=3500, (viii) an IFS spectral range of 370-970nm, and, (ix) simultaneous operation of IFS and MOS.