ESA's Euclid cosmic survey has found over 900M galaxies

The European Space Agency's (ESA) Euclid mission has made a major breakthrough in its quest to map the universe. The project, launched in July 2023, has found over 900 million galaxies and some 15,000 potential cases of strong gravitational lensing. This phenomenon could provide clues to understanding the elusive dark universe. The newly released data covers about 14% of the total sky area Euclid will map.

Unlike previous surveys, Euclid offers unparalleled detail and information content.

While the Hubble telescope has produced high-resolution images, it doesn't cover as large an area of the sky as Euclid does.

Professor Andy Taylor from the University of Edinburgh, who leads the UK science ground segment for this mission, emphasized that the technological leap that is Euclid is that we can keep that high resolution.

The first major data release from Euclid offers an unprecedented view of the cosmos.

It includes over 900 million galaxies and more than 60 million potential quasars, luminous objects at the centers of distant galaxies, powered by supermassive black holes.

The dataset also contains candidates for strong gravitational lensing, a magnification effect when one galaxy lies in front of another, distorting space-time and bending light.

Studying strong gravitational lensing could help scientists rule out different theories about dark matter.

The effect is greatly enhanced by dark matter, which increases the mass and hence the gravitational influence of a galaxy.

With strong gravitational lensing, you find out how the dark matter is clumping and that's very diagnostic of the type of matter it is, because different types of matter can clump in very different ways, said Professor Stephen Serjeant from Open University.

The Euclid data has revealed about 15,000 probable cases of strong gravitational lensing, a significant increase from the previously known 1,000 cases.

Professor Taylor expects around 170,000 such cases to be discovered by the end of the mission.

This could provide valuable insights into dark matter distribution in galaxies and its properties.

Professor Taylor also hinted at another data release expected next summer.

This will include findings on galaxy distribution and weak gravitational lensing, subtle distortions in distant objects by dark matter in the foreground.

We can use that pattern of distortions to actually make a map of where all the dark matter is in the universe, he said, adding scientists could then determine its statistical properties and compare them with different theories.