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Kavli Institute for Cosmology, Cambridge


At its meeting in December 2021, ESO Council gave permission for the agreements for the second generation spectrographs ANDES (formerly known as HIRES) and MOSAIC to be signed.  The agreements are now being discussed and drawn-up by each of the two instrument consortia with plans to kick off their Phase B design studies later this year. These innovative and complex instruments will significantly enhance the capabilities of the ELT through the effort of large teams of international scientists and engineers. Given the UK's pioneering expertise in spectroscopy, UK instrument teams have well-defined roles in both of these instruments.

ANDES and MOSAIC are highly versatile spectrographs operating from the visible to the near-infrared and will address a vast range of ground-breaking science cases. ANDES, the ELTs high resolution spectrograph, will be capable if detecting bio-markers in the Earth-like exoplanet atmospheres, find the earliest galaxies, seek possible variations of fundamental physical constants, and perform the first direct measurement of the expansion of the Universe. The multi-object spectrograph MOSAIC will use the full ELT field-of-view to capture the spectral properties of hundreds of objects or map diffuse emission in a single pointing. Among many other cases, it will address open questions in the formation and evolution of the Milky Way,  galaxy evolution across cosmic time, and the study dark and baryonic matter.