The European Space Agency's Euclid space mission has revealed the first piece of its great map of the Universe, showing the capabilities of the spacecraft's massive optical camera which was designed and built by a UCL-led team.
This first chunk of the map, which is a huge mosaic of 208 gigapixels, contains 260 observations made between 25 March and 8 April 2024. In just two weeks, Euclid covered 132 square degrees of the Southern Sky in pristine detail, more than 500 times the area of the full Moon.
This mosaic accounts for 1% of the wide survey that Euclid will capture over six years. During this survey, the telescope observes the shapes, distances and motions of billions of galaxies out to 10 billion light-years. By doing this, it will create the largest cosmic 3D map ever made.
This first piece of the map already contains some 14 million galaxies that could be used to study the hidden influence of dark matter and dark energy on the Universe. It also contains tens of millions of stars in our own Milky Way.
It was created by combining data from Euclid's two instruments: VIS, a visible light camera developed by an international team led by UCL researchers, and the Near Infrared Spectrometer and Photometer (NISP), which captures light from the infrared spectrum.
Professor Mat Page, based at UCL's Mullard Space Science Laboratory, who is the current lead for the VIS camera, said: "Before Euclid, nobody had ever made an image of such a large area of sky at such high resolution. Even the zoomed in images don't show the full resolution of Euclid's spectacular VIS camera.
"Before Euclid, we would never be able to see the faint cirrus clouds in the Milky Way, and pick out every star that's illuminating them in super-high resolution.
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The map was revealed at the International Astronautical Congress in Milan, Italy, by ESA's Director General Josef Aschbacher and Director of Science Carole Mundell.
Dr Valeria Pettorino, Euclid Project Scientist at ESA, said: "This stunning image is the first piece of a map that in six years will reveal more than one third of the sky. This is just 1% of the map, and yet it is full of a variety of sources that will help scientists discover new ways to describe the Universe."
The spacecraft's sensitive cameras captured an incredible number of objects in great detail. Zooming very deep into the mosaic (this image is enlarged 600 times compared to the full view), we can still clearly see the intricate structure of a spiral galaxy.
A special feature visible in the mosaic are dim clouds in between the stars in our own galaxy, they appear in light blue against the black background of space. They are a mix of gas and dust, also called "galactic cirrus" because they look like cirrus clouds. Euclid is able to see these clouds with its super sensitive VIS camera because they reflect optical light from the Milky Way. The clouds also shine in far-infrared light, as seen by ESA's Planck mission.
The mosaic released today is a teaser for what's to come from the Euclid mission. Since the mission started its routine science observations in February, 12% of the survey has been completed. The release of 53 square degrees of the survey, including a preview the Euclid Deep Field areas, is planned for March 2025. The mission's first year of cosmology data will be released to the community in 2026.
