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Euclid Discovers 31 Ancient Quasars, Setting a New Redshift Record for the Most Distant Quasar Ever Reported

ESA's Euclid telescope has found 31 quasars from the universe's first billion years. EUCL J172902.75+641018.1, at redshift 7.77, breaks a record that stood since 2021, and the haul more than doubles the known quasars at redshift 7 or above.

Science & Research Astronomy
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Overview

The European Space Agency’s Euclid space telescope has discovered 31 of the most ancient quasars ever found, two of which are the earliest quasars yet observed in cosmic history, according to ESA. The objects shone with the light of a trillion Suns when the universe was 670 million years old — just 5% of its current age, ESA said. The discovery paper, led by Daming Yang of Leiden University in the Netherlands, was published on July 6, 2026 in Astronomy & Astrophysics.

The highest-redshift object in the batch, EUCL J172902.75+641018.1 at a redshift of approximately 7.77, “sets the new redshift record for the most distant quasar ever reported,” the team writes in the paper. The previous record-holder, discovered in 2021, has a redshift of 7.64, according to ESA.

What We Know

  • The 31 new quasars span the redshift range 6.6 to 7.8 and were selected from approximately 3,000 square degrees of sky covered during the first 1.5 years of the Euclid Wide Survey, per the Astronomy & Astrophysics paper.
  • Twelve of the new quasars sit at redshift 7 or above, “more than doubling the number of previously known quasars at z ≥ 7,” according to the paper. That redshift corresponds to the first 770 million years of the universe, ESA noted.
  • The two most ancient of the batch, EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3, have redshifts of 7.77 and 7.69, respectively. Both lie just over 13 billion light-years away and emerged during the universe’s first 670 million years, according to ESA.
  • Candidates were identified with machine-learning and probabilistic techniques applied to Euclid’s imaging, and were confirmed through spectroscopic follow-up observations with Keck, Magellan, and the Large Binocular Telescope, the paper reports.
  • Many of the new finds are markedly fainter than earlier discoveries: the sample extends quasar studies “to the faint end of the quasar luminosity function” at redshifts of roughly 7 and above, per the paper.

Quasars are among the brightest, most energetic objects in the universe, powered by supermassive black holes devouring matter at the centers of galaxies, as Sci.News explains. During this brief phase, a galaxy’s nucleus can outshine the rest of its host galaxy by hundreds to thousands of times, according to ESA.

“These early quasars date back to the Universe’s infancy,” said Yang, the lead author, in an ESA statement. “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.”

“This finding more than doubles the number of quasars we know of that are so ancient,” said Antonio La Marca, an ESA Research Fellow in the Euclid team, per ESA. Discovering the first 10 or so quasars at redshift 7 or above took astronomers more than a decade, while Euclid found more than that in a single year, ESA noted.

A companion study by Silvia Belladitta and collaborators examined the second most ancient quasar in more detail, showing it is embedded in a dusty, gas-filled galaxy that is furiously forming new stars, according to ESA.

What We Don’t Know

  • How the first supermassive black holes formed and grew so quickly remains an open question — one Yang called “one of the greatest mysteries in astrophysics” in the ESA statement.
  • The announcements did not disclose mass estimates for the black holes powering the newly found quasars.
  • The paper frames the discoveries as setting the stage for “future follow-up studies of the early galaxies hosting quasars, supermassive black hole growth, and the intergalactic medium in the epoch of reionisation,” per Astronomy & Astrophysics — work that has yet to be carried out.

Analysis

The significance of the result lies less in the record itself than in the population it reveals. Earlier searches could only recover the rare, bright outliers among early quasars; ESA describes the new sample as capturing “not just the bright outliers but most of the ancient quasar population,” per the agency’s announcement. “The Euclid team has taken a true ‘census’ of quasars at the dawn of the Universe for the first time,” La Marca said in the same statement.

Quasar hunting is a byproduct of Euclid’s primary mission: the telescope, which launched in July 2023 and began routine science observations on February 14, 2024, is mapping the large-scale structure of the universe to probe its dark components, observing billions of galaxies as it goes, according to ESA. The Euclid Wide Survey that yielded these quasars will cover more than one-third of the total sky once complete, ESA said — and the survey has already produced other side results, such as the stellar catalog of the Milky Way’s bulge previously reported by The Machine Herald.

“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,” said ESA Euclid Project Scientist Valeria Pettorino in the announcement.