PARIS, FRANCE. The European Space Agency Euclid space telescope was designed to map the distribution of dark matter and dark energy across the large-scale structure of the cosmos. In July 2026, it proved itself something else entirely: the most efficient quasar hunter ever launched. A collaboration of hundreds of astronomers across multiple institutions published findings on July 6 in Astronomy and Astrophysics announcing the discovery of 31 previously unknown quasars from the earliest epochs of cosmic history. Among them, two shattered every existing distance record for such objects.
What Are Quasars | The Universe's Most Luminous Cosmic Beacons
Quasars represent a brief, intense phase of galaxy evolution. At the center of nearly every large galaxy sits a supermassive black hole, dormant for most of cosmic history. When a galaxy is young and dense with gas, that central black hole enters a feeding frenzy, aggressively consuming infalling material. The infall creates an accretion disk, a swirling structure of gas and dust heated by gravitational compression and friction to temperatures of millions of degrees. The energy released in this process is extraordinary: a quasar outshines every single star in its host galaxy combined. Some quasars are brighter than a trillion Suns. Because they are so luminous, they remain visible across distances spanning billions of light-years, functioning as lighthouses marking the locations of the very first galaxies.
Identifying quasars from the first 700 million years of cosmic history has historically been slow and error-prone. Because the universe was expanding rapidly during this period, their light is stretched toward the red end of the spectrum, a process called cosmological redshift. At the high redshifts corresponding to the earliest epochs, quasar light is shifted so far into the near-infrared that ground-based optical surveys miss most of them entirely, and the ones that are detected can be confused with red dwarf stars or brown dwarfs at far closer distances. Euclid near-infrared instrumentation, combined with its ability to survey enormous sky areas quickly, changes that calculation entirely.
The 31 Discoveries | Two Shatter the Distance Record
The Euclid team identified 31 quasar candidates through a combination of visible and near-infrared imaging, then confirmed the most distant with follow-up spectroscopy at the Keck Observatory in Hawaii and the Subaru Telescope at Mauna Kea. The two record-holders are designated EUCL J172902.75+641018.1 at redshift 7.77 and EUCL J125308.55+705432.3 at redshift 7.69. At these distances, the light now reaching Euclid detectors left these objects when the universe was approximately 670 million years old, roughly five percent of its current age of 13.8 billion years.
Equally significant is the statistical impact. Prior to this survey, astronomers had catalogued only a handful of quasars at redshift 7 or above. The Euclid sweep added 12 new confirmed objects in that range in a single dataset, more than doubling the known population from that epoch. This transforms the study of early-universe quasars from a collection of curiosities into a statistical sample large enough to study as a class, mapping their spatial distribution, brightness range, and host galaxy properties systematically.
The Black Hole Growth Problem | Too Big, Too Soon
The existence of quasars at redshift 7 and above presents one of the most serious unresolved problems in modern astrophysics. The black holes powering these quasars are estimated to contain masses between hundreds of millions and several billion times the mass of our Sun. Standard accretion models have a fundamental rate limit: a black hole feeding on gas emits so much radiation that it eventually pushes the infalling material away, creating a natural ceiling on how fast it can grow called the Eddington limit. Running the growth models backward from the observed black hole masses to the expected seed black holes at the start of the universe leaves an enormous gap.
Several competing explanations have been proposed. One scenario invokes direct collapse black holes, hypothetical seeds formed directly from massive primordial gas clouds rather than through stellar death, which could start the growth process from a much higher initial mass. Another invokes sustained super-Eddington accretion episodes where infalling gas temporarily overwhelms the radiation pressure limit. A third proposes that early black holes grew through rapid sequential mergers in the densely packed early universe. The expanded Euclid quasar sample gives theorists their first large-scale observational dataset to test these models against, constraining which scenarios are physically plausible at the observed abundances.
Euclid as a Quasar Hunter | Why Wide-Field Infrared Changes Everything
Euclid primary mission remains dark matter and dark energy mapping. Its Euclid Wide Survey will image more than one-third of the entire sky over the telescope six-year operational period, reaching depths and sky coverage no previous survey instrument could achieve. The quasar discoveries are a scientific byproduct of this mapping campaign, emerging from the same imaging data collected for large-scale structure analysis. This means the quasar catalog will grow continuously as the survey progresses, with astronomers expecting to discover hundreds of additional high-redshift quasars across the full dataset.
The key technical advantage is Euclid combined visible and near-infrared camera system operating from space, above atmospheric interference that blurs and absorbs infrared wavelengths. At the redshifts corresponding to the earliest quasars, the most diagnostically useful spectral features have been shifted from the ultraviolet into the near-infrared. Ground-based surveys see only a fraction of the signal. Euclid captures all of it across enormous sky areas simultaneously, making the detection of rare high-redshift objects statistically inevitable across a survey of this scale.
For more on space telescope discoveries and the early universe, see OzoneNews coverage of the galaxy-killing wind observed by JWST in the early universe and the Milky Way black hole wind discovery at Sagittarius A. Related science coverage includes the AION atom interferometer dark matter detection breakthrough and the Nancy Grace Roman Space Telescope arrival in Florida.