Euclid data lay groundwork for the universe’s largest 3D map

The European Space Agency has released the first comprehensive observations from its Euclid space telescope, laying the groundwork for the largest 3D map of the cosmos, ORF reported. The data include more than a billion objects recorded over 13 months, including more than 900 million galaxies.

Euclid also identified about 15,000 gravitational lens candidates, 60 million potential quasars and numerous dwarf galaxies. Innsbruck astronomer Francine Marleau, a scientific adviser to the mission, specialises in dwarf galaxies.

Based on an initial analysis of a smaller part of the sky last year, Marleau estimates the new data contain several hundred thousand dwarf galaxies. Their low brightness and mass make them difficult to study. She expects Euclid to provide data on more than two million dwarf galaxies after six years, when it will have surveyed about a third of the sky.

The telescope combines sensitivity to faint structures, high resolution and wide sky coverage. The latest release includes optical and near-infrared observations covering 1,900 square degrees, equivalent to about 9,500 full moons. The data amount to 1.7 million gigabytes.

Euclid is intended to investigate unanswered questions about dark energy and dark matter, which make up most of the universe. Stars, planets, galaxies and other known components account for about five percent.

The telescope, launched in mid-2023, is positioned about 1.5 million kilometres from Earth, orbiting the second Lagrange point. Its observations can reveal rare and distant objects, including strong gravitational lenses and galaxy clusters, that are difficult to detect from the ground because Earth’s atmosphere distorts and dims light.

The new release includes the largest catalogue of strong gravitational lenses compiled to date, larger than all previous catalogues of this kind combined. These lenses form when the gravity of a massive object, such as a galaxy, significantly bends light from a more distant galaxy. Studying them can help astronomers map mass in the universe and estimate the mass of individual galaxies, including their dark matter.

ESA science director Carole Mundell called the release a scientific milestone. The data will also allow researchers to estimate the distances to individual galaxies and place them within the universe’s 3D structure.