Euclid Discovers Ancient Quasars From the Universe’s First Era

Euclid has opened a new window onto cosmic dawn by identifying 31 exceptionally ancient quasars. Two are described as the oldest observed, shining when the universe was only about 5% of its present age. The result is more than a record: it provides a population for studying how giant black holes appeared so soon after the Big Bang.

What is a quasar?

A quasar is the intensely luminous core of a galaxy whose supermassive black hole is consuming gas and dust. Material spiraling inward heats up and emits radiation visible across billions of light-years, sometimes outshining the entire host galaxy.

Such objects create a timing problem. Growth from a small stellar-remnant black hole may be too slow to reach hundreds of millions or billions of solar masses within the available cosmic time.

Why 31 objects matter

One ancient quasar can be exceptional; a population enables statistical testing. Researchers can compare luminosities, environments and masses to distinguish competing origin theories.

• Light seeds: remnants of the first stars grew rapidly.
• Heavy seeds: primordial gas clouds collapsed directly into larger black holes.
• Accelerated growth: dense early galaxies and mergers enabled repeated feeding.

Euclid’s special role

Euclid maps vast areas of sky consistently, making it an efficient finder of rare objects. James Webb can study faint targets in extraordinary detail, while Euclid identifies candidates across a much larger volume. Together they create a discovery-and-follow-up system.

What comes next?

Spectroscopy must confirm distances and examine the surrounding gas. X-ray and infrared observations can estimate feeding rates and uncover dust-hidden objects. Host galaxies may reveal whether black holes or galaxies grew first. By expanding the sample, Euclid turns origin theories into models that can be tested against a population.