What Euclid Has Actually Found About Ancient Quasars — And What It Hasn't (As of Mid-2026)

3,500 Bright Quasars with Measured Redshifts

A dedicated Euclid spectroscopy paper (arXiv 2512.08803) identifies and determines redshifts for 3,500 bright quasars — a major step forward for statistical studies of the quasar population .

A Candidate Dual Quasar System

A study on red quasars selection (arXiv 2503.15319) showcases Euclid's near-infrared photometry, revealing a candidate dual quasar system — two quasars in close physical proximity, likely representing a merger of two galaxies with active black holes . The same study produced a catalog of more than 150,000 red quasar candidates, providing a first census for future work with the Euclid Wide Survey .

7,000 Candidate Quasars Expected

ESA has stated that Euclid's deep fields contain a "small population of bright quasars that can be seen much farther away" and that the mission expects to capture some 7,000 candidate quasars overall .

What Euclid Has NOT Found (Yet)

Despite these impressive results, the specific claim about the "two oldest quasars ever found" on July 6, 2026, is unsubstantiated. Here is why:

The Farthest Known Quasar Is Still UHZ1

As of mid-2026, the farthest known quasar remains UHZ1 at redshift z ~ 10.1, seen approximately 13.2 billion light-years away, about 400 million years after the Big Bang . This discovery was made by other observatories, not Euclid.

The Oldest Known Supermassive Black Hole: J0313-1806

The oldest known supermassive black hole (from quasar J0313-1806 at z = 7.64, dating to approximately 670 million years after the Big Bang) was discovered in 2021 by an international team led by the University of Arizona, again without Euclid involvement .

The Earliest Known Flickering Quasar

On June 8, 2026 — less than a month before the unsubstantiated claim — MIT announced the discovery of the earliest known flickering quasar, traced to just 850 million years after the Big Bang . This was a significant finding, but it was not a Euclid discovery; it came from MIT researchers analyzing data from other observatories .

The Big Picture: Why Euclid's October 2026 Data Release Matters

Euclid's first cosmology data is scheduled for public release in October 2026 . This release will include deep-field observations collected over multiple passes, providing significantly deeper sensitivity to high-redshift quasars. Any major quasar discovery involving "the two oldest quasars ever found" with specific redshift and distance details would most likely be announced at or after that data release.

Simulations show that synergies between Euclid, the Roman Space Telescope, and JWST could reveal quasars at redshifts up to z ~ 14–15, potentially detecting black holes like UHZ1 and GHZ9 at much earlier stages of evolution . This is the kind of breakthrough that astronomers are genuinely anticipating — but it has not happened yet.

How to Verify Future Euclid Announcements

For anyone tracking Euclid's real discoveries, the official sources to monitor are:

• ESA Euclid page: esa.int/Science_Exploration/Space_Science/Euclid
• Euclid Consortium press releases: euclid-ec.org/public/press-releases
• NASA's Euclid mission page: science.nasa.gov/mission/euclid
• ESA Euclid news archive: cosmos.esa.int/web/euclid/news-archive-2026

A Note on Quasar Discovery Pace

The unsubstantiated claim that July 6, 2026 marked the discovery of the "two oldest quasars ever found" is particularly questionable because it ignores the established discovery timeline. It took astronomers from 2011 (ULAS J1120+0641 at z=7.1) to 2021 (J0313-1806 at z=7.64) to push the quasar redshift record by just 0.54 . The leap to discovering multiple quasars older than the current record holder in a single announcement would be unprecedented — and there is no evidence it occurred.

If you encounter an article making this claim, verify it against the official sources above. As of mid-2026, Euclid is delivering valuable quasar science at an impressive scale, but the "two oldest quasars ever found" remain undiscovered.