James Webb Space Telescope Finds Oldest Quasar Pair, Study Says

Nine hundred million years after the Big Bang, two supermassive black holes had already reached 1.5 billion and 400 million solar masses — a pairing no model predicts.

The pair, designated J1602+4228AB and nicknamed Nāpōwawāʻenakaulua, is the oldest compact quasar pair ever observed.

Seen when the universe was 900 million years old, the quasars sit about 18,100 light-years apart, roughly one-fifth the Milky Way’s diameter. The findings were published Nov. 10 in The Astrophysical Journal Letters.

The announcement came Nov. 10, 2026, from NSF NOIRLab, the National Science Foundation center for ground-based optical-infrared astronomy.

NOIRLab operates the International Gemini Observatory with partners including NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea, plus NSF Kitt Peak National Observatory, NSF Cerro Tololo Inter-American Observatory, the Community Science and Data Center, and the NSF–DOE Vera C. Rubin Observatory.

The system lies toward the constellation Boötes, more than 12.9 billion light-years from Earth.

Standard models say black holes need at least a billion years of feeding and mergers to reach millions or billions of solar masses. Since the James Webb Space Telescope began operating in 2022, it has routinely found supermassive black holes as early as 400 million years after the Big Bang — and now two side by side.

The growth problem is sharpened by physical limits: matter cannot fall into a black hole at an arbitrarily high rate because gas near the event horizon heats up, emits radiation, and the resulting pressure pushes remaining material away.

Starting from a stellar remnant as the initial seed, growing to a billion solar masses would have demanded accretion at close to the theoretical maximum pace for nearly all of the time elapsed since the Big Bang. Other suggested seed types — for example, direct collapse black holes that bypassed the stellar phase and were born with 10,000 to 100,000 solar masses — are still purely theoretical.

“There is no definitive theoretical explanation for how a single one of these giant quasars exists so early in the age of our Universe, much less two,” said Silvia Onorato, a postdoctoral researcher at NSF’s NOIRLab who led the study.

Quasars shine when gas spirals into the black hole through an accretion disk, heating up and glowing brighter than every star in the host galaxy combined. Finding two of them this close, this early, is rare: a black hole’s quasar phase is short, distant objects are faint, and pair members so near together are hard to resolve.

Found Inside a Census of 200 Quasars

The companion surfaced in data from the Aether survey, a JWST program that used the telescope’s Near-Infrared Spectrograph to examine a sample of 200 early-universe quasars — 43 percent of all known quasars from that era. Reviewers spotted a faint companion, later designated J1602+4228B, at almost the same distance as the known quasar J1602+4228A.

The Aether Survey is a James Webb Space Telescope Cycle 3 observing program conducting a census of objects in the early universe. The initial search began with the Subaru Hyper Suprime-Cam, a wide-field optical-to-near-infrared imager, while data from the Euclid mission extended the inventory of known Cosmic Dawn quasars, providing context for the environments where compact pairs might form.

A system called LID-1166, spotted in August 2026 through combined JWST and ALMA observations, was recognized as a dual active galactic nucleus at high redshift, showing that paired black hole activity in the early universe is not a one-off occurrence.

The team confirmed the second object with the Gemini Near-Infrared Spectrograph on the Gemini North telescope on Maunakea, and data from Gemini’s Multi-Object Spectrograph showed the two spectra differ enough that a gravitational lens — one quasar split into two images — is considered unlikely. The fainter quasar is about 19 times dimmer than its partner, separated by just under one arcsecond on the sky.

JWST’s NIRSpec Integral Field Unit, which captures a spectrum for every spatial position within a small field of view simultaneously, provided the first spectra of the two individual sources, confirming their redshifts at about z≃6.0781 and z≃6.0785.

The pair’s quasars show different spectral slopes and differing amounts of dust extinction, while the high-velocity gas outflows traced by their oxygen emission lines display distinct profiles — something gravitational lensing cannot alter. Archival Hubble images show a possible foreground galaxy near the fainter quasar.

Gemini North’s GNIRS spectra resolved the two quasars as physically distinct objects at essentially the same redshift, confirming they form a physically bound system rather than a line-of-sight coincidence. Together the two black holes total nearly 2 billion solar masses. Astronomers weigh such distant black holes by measuring the width of hydrogen emission lines from gas orbiting them.

For scale, Sagittarius A* at the Milky Way’s center weighs about 4 million solar masses, making the larger black hole in the pair more than 300 times heavier. The separation between the pair is shorter than the distance between our Sun and the center of the Milky Way.

We observed Nāpōwawāʻenakaulua at a time when the Universe was only a thirteenth of its age and astonishingly, its supermassive black holes are just as massive as those we see today. Onorato said

A Name for Two Giants

The Hawaiian name translates as “Two celestial bodies of fathomless powerful darkness in the brilliance of heat reincarnating energy into the Universe.” Created to honor the cultural and spiritual importance of Maunakea for the Native Hawaiian community, the program has previously given names to quasars such as Pōniuāʻena, found in 2020.

It's a laboratory for astronomers to study how the very first massive galaxies and their central black holes assembled together through direct galaxy interactions during these early times. Onorato said

The researchers suggest this uncommon quasar pair could mark an extreme overdensity in the early Universe’s matter distribution, a place where galaxy interactions at once triggered star formation and the swift growth of the black holes.

Galaxies frequently collided in the early Universe, so pairs of supermassive black holes should be common — but finding them is difficult. Should galaxy interactions in that region have driven both star formation and fast black hole growth simultaneously, additional galaxies probably lie nearby, so looking for that neighboring population is the next step.

The findings appear in The Astrophysical Journal Letters as Onorato et al., “Nāpōwawā‘enakaulua: A Close Quasar Pair at Cosmic Dawn in the Aether Survey,” ApJL 1011, L59, doi: 10.3847/2041-8213/aeb11f.

The pair is the third quasar pair known from cosmic dawn. At a redshift of about 6.08, its light has traveled roughly 12.9 billion years.