The Blue Multi Unit Spectroscopic Explorer (BlueMUSE) - science drivers and overview of instrument design

BlueMUSE (Blue Multi Unit Spectroscopic Explorer) is a blue-optimised, medium spectral resolution, panoramic integral field spectrograph under development for the Very Large Telescope. With an optimised transmission down to 350 nm, a large FoV (1 arcmin2) and a higher spectral resolution (λ/Δλ ~ 4000) compared to its predecessor MUSE, BlueMUSE will open up a new range of galactic and extragalactic science cases allowed by its specific capabilities in the 350-580nm range. Among the science goals available with BlueMUSE, it will survey large sample of massive stars in our galaxy and the Local Group, study ionized nebulae, starburst and low surface-brightness galaxies. At high redshift, it would allow us for the first time to detect the IGM unambiguously in emission, as well as study the evolution of the CGM properties near the peak of the Cosmic Star formation history. As part of the VLT2030 suite of instruments under development for the VLT, BlueMUSE capabilities will be complementary to future facilities like JWST and the ELT, which will focus on red and near-infrared wavelengths. I will present an overview of the BlueMUSE instrument science requirements and design, focusing on the technical challenges and the lessons learned from MUSE, where we expect significant improvements, as well as the synergies with upcoming facilities.