The Blue Multi Unit Spectroscopic Explorer (BlueMUSE) on the VLT: science drivers and overview of instrument design

TL;DR

BlueMUSE is a planned blue-optimized integral field spectrograph for the VLT, designed to enable new galactic and extragalactic science with high spectral resolution and a large field of view, expected to be operational by 2031.

Contribution

This paper presents the design overview, science drivers, and key system tradeoffs of BlueMUSE, a new instrument building upon the existing MUSE system for the VLT.

Findings

BlueMUSE will operate down to 350 nm with R~3500 spectral resolution.

It features a 1 arcmin^2 field of view for panoramic observations.

The instrument design emphasizes specific tradeoffs to meet science requirements.

Abstract

BlueMUSE is a blue-optimised, medium spectral resolution, panoramic integral field spectrograph under development for the Very Large Telescope (VLT). With an optimised transmission down to 350 nm, spectral resolution of R$\sim$3500 on average across the wavelength range, and a large FoV (1 arcmin$^2$), BlueMUSE will open up a new range of galactic and extragalactic science cases facilitated by its specific capabilities. The BlueMUSE consortium includes 9 institutes located in 7 countries and is led by the Centre de Recherche Astrophysique de Lyon (CRAL). The BlueMUSE project development is currently in Phase A, with an expected first light at the VLT in 2031. We introduce here the Top Level Requirements (TLRs) derived from the main science cases, and then present an overview of the BlueMUSE system and its subsystems fulfilling these TLRs. We specifically emphasize the tradeoffs that are made and the key distinctions compared to the MUSE instrument, upon which the system architecture is built.