The CUBES Science Case

TL;DR

The paper presents the scientific motivations, technical design, and expected performance of the CUBES spectrograph for the VLT, aiming to significantly enhance ultraviolet observations across various astronomical fields.

Contribution

It introduces the design and expected capabilities of CUBES, a new spectrograph that offers tenfold efficiency improvements in the 300-405nm range for ground-based astronomy.

Findings

CUBES will observe sources up to three magnitudes fainter than current instruments.

It achieves a factor of ten gain in efficiency over 300-405nm wavelengths.

Designed for resolving powers of R~24,000 and R~7,000.

Abstract

We introduce the scientific motivations for the development of the Cassegrain U-Band Efficient Spectrograph (CUBES) that is now in construction for the Very Large Telescope. The assembled cases span a broad range of contemporary topics across Solar System, Galactic and extragalactic astronomy, where observations are limited by the performance of current ground-based spectrographs shortwards of 400nm. A brief background to each case is presented and specific technical requirements on the instrument design that flow-down from each case are identified. These were used as inputs to the CUBES design, that will provide a factor of ten gain in efficiency for astronomical spectroscopy over 300-405nm, at resolving powers of R~24,000 and ~7,000. We include performance estimates that demonstrate the ability of CUBES to observe sources that are up to three magnitudes fainter than currently possible at ground-ultraviolet wavelengths, and we place its predicted performance in the context of existing facillities.