Euclid Discovers the Most Ancient Quasars in the Universe

The Discovery: 31 Ancient Quasars

ESA's Euclid space telescope has discovered an unprecedented 31 new quasars in the early Universe, pushing back to a time when the cosmos was just 5% of its current age. The findings, published July 6, 2026 in Astronomy & Astrophysics, add 12 quasars at a redshift of 7 or above — corresponding to the first 770 million years of the Universe — more than doubling the number of known quasars from this ancient epoch.

"These early quasars date back to the Universe's infancy," says Daming Yang of Leiden University in the Netherlands, lead author of the Euclid discovery paper. "By finding and studying them, we can better understand how these enormous systems formed and grew so quickly — one of the greatest mysteries in astrophysics."

Quasars are among the most luminous objects in the cosmos, powered by supermassive black holes at the centres of distant galaxies. During its brief quasar phase, a galaxy's nucleus outshines everything else in the Universe, often shining hundreds to thousands of times brighter than the rest of its host galaxy combined.

The Record-Breakers: Redshift 7.77 and 7.69

The two most ancient quasars in the batch have shattered the previous distance record. Designated EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3, these cosmic giants have redshifts of 7.77 and 7.69 respectively — surpassing the previous record-holder (redshift 7.64, discovered in 2021) and setting a new milestone for the most ancient quasars ever observed.

Both objects lie just over 13 billion light-years away and emerged during the Universe's first 670 million years. They blazed with a luminosity that outshines entire galaxies, powered by supermassive black holes that had already grown to enormous sizes in what astronomers consider a remarkably short time after the Big Bang.

The second most ancient quasar was studied in detail by Silvia Belladitta and collaborators, revealing that it is embedded in a dusty, gas-filled galaxy that is furiously forming new stars — providing rare insight into what the host galaxy of an early supermassive black hole looks like.

What This Means for Astronomy

The earliest quasars known until now were the rare, exceptionally bright outliers — the ones easiest to spot. Astronomers had simply not found enough of them to study as a population. Astronomers had not found enough quasars from the Universe's early days to study them properly as a group. Euclid's new finding changes that fundamentally, capturing not just the bright outliers but most of the ancient quasar population.

"Euclid is a true game-changer," says Daming Yang. "Before, we could only find a handful of the very brightest ancient quasars, but Euclid lets us search far more efficiently across huge areas of sky to capture much fainter light. It's a unique tool for quasar hunting."

Discovering the first 10 or so quasars at a redshift of 7 or above took astronomers more than a decade. Euclid has already discovered more than that in a single year. "The Euclid team has taken a true 'census' of quasars at the dawn of the Universe for the first time," adds Antonio La Marca, an ESA Research Fellow on the Euclid team. "It's a big step towards understanding these fascinating objects on a more fundamental level."

"Ancient quasars are rare discoveries. They're interesting in themselves, but also time machines that enable us to explore the early Universe and understand how the first generation of galaxies came to be," says ESA Euclid Project Scientist Valeria Pettorino.

The Epoch of Reionisation

These quasars hark back to a fascinating period in cosmic history known as the epoch of reionisation — when the Universe shifted from being cold and dark (the cosmic dark ages) to hot and ionised, split apart by energetic light from the first stars and galaxies. This transitional epoch was a crucial era that set the stage for everything we see today.

Understanding how supermassive black holes grew to millions or billions of solar masses in the first few hundred million years after the Big Bang remains one of the greatest unsolved problems in astrophysics. The discovery of 31 new ancient quasars provides astronomers with a statistically significant sample to begin answering this question — revealing how common these objects were, how quickly they grew, and what role they played in shaping the early Universe.

Why Euclid Is a Game-Changer

Launched in July 2023, Euclid began its routine science observations in February 2024. The telescope was designed primarily to study dark energy and dark matter by mapping the large-scale structure of the Universe across more than one-third of the sky. But its combination of wide-area coverage, depth, sharp imaging, and space-based infrared vision makes it uniquely suited to finding rare, extremely distant objects like ancient quasars.

"Euclid's capabilities are unrivalled," says Pettorino. "The telescope combines a large area, depth, sharp imaging, and unique space-based infrared vision in a way that lets us pick out rare, extremely distant objects far more efficiently than before." The 31 quasars were discovered in data from the Euclid Wide Survey, which will cover more than one-third of the total sky once complete — meaning many more ancient quasars are likely waiting to be found.

Euclid is a European mission built and operated by ESA, with contributions from its member states and NASA. The Euclid Consortium — more than 2,000 scientists from 300 institutes in 15 European countries, the USA, Canada, and Japan — is responsible for the scientific instruments and data analysis.

Frequently Asked Questions

Sources

• ESA — Euclid Discovers the Most Ancient Quasar in the Universe (Original Press Release)
• ESA — Artist's Concept of an Ancient Quasar (Image)
• Astronomy & Astrophysics — Discovery of 31 new quasars at 6.6<z<7.8 by D. Yang et al. (Research Paper)

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