VLT: The MUSE instrument unveilsan unknown “cosmic web” in the Universe
In Spring 2021, the Very Large Telescope (VLT), equipped with the Multi-Unit Spectroscopic Explorer MUSE, captured the first direct image of a myriad of unsuspected dwarf galaxies: a remarkable discovery for the European Southern Observatory (ESO)!
Located in Chile, the flagship facility for European ground-based astronomy allowed the discovery of hydrogen filaments stretching across 15 million light years, within which galaxies form. Although known to astronomers, this phenomenon had never been observed before.
The ESO second-generation VLT instrument MUSE observes galaxies that are slightly more than 10 billion light years away, hence the challenge, since deep-sky objects look tiny and extremely faint.
To fulfil such a difficult task, the VLT has been equipped with the integral field spectrograph MUSE, whose project was initiated and led by Roland Bacon, astronomer and Director of Research at CNRS*. This revolutionary instrument allows for the exploration of the Universe in three dimensions, as well as the search for young galaxies, regardless of their distance, by observing the sky in the direction of the Southern Hemisphere. In order to probe a wide field of view, MUSE uses twenty-four 3D spectrographs, coupled with an adaptive optics system. The latter corrects atmospheric perturbations in real time, as they interfere with the luminous signal of young galaxies and mask their detection. With its 370 million pixels, the instrument can also cover a complete field of view and analyse both spatial and spectral information simultaneously.
Winlight System participated in the design of the instrument by supplying more than 2,500 optical components and complex subsystems, including:
- 24 image slicers, designed to “cut into slices” the complete field of view of the VLT in order to create a mosaic of images that can then be analysed by the spectrographs.
- 24 spectrographs, to cover a complete field of view and analyse all objects simultaneously.
- A field splitter.
- A derotator.
- 48 transport doublets.
Either fixed or moving, these optical components and complex subsystems have been operating since 2014 and continue to deliver high performance. Winlight System is proud to have actively participated in the design and development of such a leading-edge instrument, which could one day help improve understanding of the early stages of galaxy formation and evolution.
*CNRS: Centre national de la recherche scientifique (French National Centre for Scientific Research).