The European Space Agency’s Euclid mission released data covering more than 900 million galaxies on November 12, 2026. The DR1-Foundation release contains about 13 months of observations, including images, catalogs and spectra that researchers can use to study the distribution of matter across the universe.
The release includes around 15,000 strong gravitational lens candidates, more than 60 million quasar candidates and spectra from more than 160 million sources. Its wide-survey observations cover 1,900 square degrees, with a total data volume of 1.7 million gigabytes.
Euclid, an ESA mission with NASA contributions, launched on July 1, 2023. It is designed to investigate dark matter and dark energy by mapping the universe in three dimensions.
A photograph locates objects across the sky. Adding distances gives the third dimension, allowing researchers to examine how galaxies are arranged through space instead of treating every object as a point on the same surface.
Measuring Distance With Light
Euclid uses spectroscopy to measure galactic light. The instrument separates incoming light into wavelengths. Gases produce recognizable spectral features, giving scientists markers that can be compared with their known positions.
One target is hydrogen-alpha emission from star-forming hydrogen clouds. The position of this emission in a galaxy’s spectrum supplies information used to determine its distance. Applying that method to many galaxies supports construction of a three-dimensional map.
The map describes the large-scale arrangement of matter. Galaxies occupy concentrations connected through the cosmic web, and their positions help researchers study how that structure developed.
The two observational tasks are connected but distinct: imaging records shapes and positions across the sky, and spectroscopy supplies information about distance and composition. The released data make both types of measurement available for analysis.
Finding Gravitational Lenses
The University of British Columbia’s account describes how researchers selected potential gravitational lenses. Machine-learning systems first identified likely examples. Citizen scientists then examined those selections, followed by expert review. Other telescopes supply follow-up observations used to confirm candidates.
Gravitational lensing occurs when foreground matter bends light from a more distant source. The resulting arcs, distorted images or rings carry information about the mass and distribution of the foreground object, including its dark matter.
The same effect can magnify the background galaxy. Researchers can use that magnification to examine objects whose light would otherwise be harder to study. This makes a lens useful both for investigating the intervening mass and for observing the more distant source.
UBC reported that the release is described in 26 papers submitted to Astronomy & Astrophysics. Its account identifies participation by Canadian researchers alongside the wider international consortium.
DR1-Foundation covers approximately 14% of Euclid’s planned survey area. The full Data Release 1, scheduled for mid-2027, is planned to add weak-lensing measurements and further information about galaxies and clusters within the cosmic web.
