Euclid telescope uncovers 31 ancient quasars, including two oldest known

Researchers using the European Space Agency's Euclid space telescope have identified 31 ancient quasars, the most luminous galactic nuclei powered by supermassive black holes. Among them are two quasars dated to about 13.1 billion years ago, roughly 670 million years after the Big Bang, placing them in the Universe's reionisation epoch.

The study, led by Daming Yang, a doctoral researcher at the Leiden Observatory, explains that gas and dust spiralling into the black holes become extremely hot and emit light far brighter than their host galaxies. Co‑author Joseph Hennawi said the findings challenge current models of black‑hole growth, suggesting either massive initial seeds or faster‑than‑expected accretion. Published in *Astronomy & Astrophysics*, the discovery highlights Euclid’s broader scientific value beyond its primary mission to investigate dark energy and dark matter after its 2023 launch.