Euclid Releases 13 Months of Data on Over One Billion Objects
ESA's Euclid telescope released its first big data set, covering 1900 square degrees of sky and more than one billion objects, for a 3D map of the cosmos.
The European Space Agency’s Euclid space telescope has released a data set called DR1-Foundation that covers a sky area as large as about 9,500 full moons and captures light from more than one billion objects, according to Universe Today. Gathering the observations took about 13 months.
The release comes from Euclid’s Wide and Deep Surveys, the two surveys that will form the backbone of its planned 3D map of the sky. It spans 1900 square degrees, which is only about 14% of the sky the telescope will cover during its six-year mission.
How the two surveys divide the work
The Wide Survey is Euclid’s primary campaign. It is an imaging and spectrographic survey in visible and near-infrared light, and it will cover almost half of the galactic sky. As the telescope’s main cosmology survey, it is built to cover a large volume of space so that scientists can constrain dark energy and dark matter.
The Deep Survey targets regions inside the Wide Survey. It looks for fainter objects such as dwarf galaxies, low-mass galaxies and tidal tails, along with high redshift galaxies and quasars. It also calibrates the Wide Survey, and its higher density of sources supports science of its own. In short, the Wide Survey supplies volume and the Deep Survey supplies depth, and a cosmological survey needs both.
Earlier Euclid releases were much smaller. One covered 60 square degrees of sky from a few days of observations. Images from the 2024 Early Release Observations and the 2025 Quick data release 1 can be explored at ESA Sky.
Three galaxy images from the release
One image shows the core of the Messier 81 galaxy group, centered on Messier 81, the group’s largest member. The smaller NGC 3077 sits on the left, and many other small members are spread across the frame. Wispy blue clouds sometimes called galactic cirrus clouds are visible, as is an irregular dwarf galaxy in diffuse blue.
Euclid also imaged NGC 1291, a ring galaxy about 33 million light years away that faces Earth head-on. Known as the Golden Eye galaxy, it has an inner ring, an outer ring and an inner bar. Its rings may come from a merger with a gas-rich galaxy in the past.
A third image shows Abell 3128, about 800 million light years away, which contains hundreds of individual galaxies. It belongs to the Horologium supercluster, home to more than 30 smaller clusters. A gravitational lens in the middle of Abell 3128 warps and magnifies light from a distant background galaxy. The frame also catches part of another cluster, ACT-CL J0330-5227. The two are separated by around 5 billion light-years but overlap along our line of sight.
Massive clusters like Abell 3128 act as gravitational lenses and show where dark matter is concentrated. Universe Today notes that they can help cosmologists test Lambda-Cold Dark Matter, the standard Big Bang theory, and that they help Euclid calibrate itself.
Why it matters for the 3D map
Dark energy and dark matter show their effects at large scales. By charting galaxy superclusters, the filaments they sit on and the voids between those filaments, Euclid is meant to improve understanding of both.
Other efforts to map this structure have run for decades. DESI, a ground-based survey, has produced the largest 3D map so far. Universe Today reports that Euclid’s map will be larger, with more depth and volume. Because Euclid works from space, it avoids atmospheric interference and should reach a higher resolution.
Euclid has already discovered a new comet, the most ancient quasar in the Universe and new images of the crowded center of the Milky Way, according to Universe Today.
Source: Universe Today
