Plate Nº 52 · recorded November 13, 2026
Space & AstronomyReported finding
Two Giant Quasars Test Black Hole Growth at Cosmic Dawn
Two apparent quasars less than an arcsecond apart, dating to 900 million years after the Big Bang, may point to the dense environments where early giant galaxies formed.
By Priya Raman3 min read695 words
In brief
- The two apparent quasars date to a universe only 900 million years old.
- Their black holes have estimated masses of 1.5 billion and nearly 400 million Suns.
- The pair appears 18,100 light-years apart on the sky and less than one arcsecond apart.
- Both apparent quasars feed near the Eddington limit, the maximum rate allowed by current models.
- The inferred small-scale quasar concentration is roughly 100 to 1,000 times higher than extrapolated expectations, but rests on one candidate.
When the universe was only 900 million years old, Silvia Onorato and colleagues identified two apparent quasars, one with a black hole estimated at 1.5 billion times the Sun’s mass and the other at nearly 400 million solar masses.
The pair lay just 18,100 light-years apart on the sky. The study identifies them as the most compact known quasar-pair candidate from cosmic dawn, the early era when the first galaxies began to form.
The objects, formally designated J1602+4228AB, are quasars: supermassive, or exceptionally massive, black holes actively feeding on surrounding matter. Black holes themselves do not emit light, but swirling gas heats to extraordinary temperatures and releases radiation intense enough for one quasar to outshine every star in its host galaxy, the galaxy that contains it.
Two quasars this massive, this close and this early strained existing explanations of black hole growth.
Silvia Onorato, an NSF NOIRLab postdoctoral research associate who led the study in The Astrophysical Journal Letters, said: “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.”
The candidate pair carries the Hawaiian name Nāpōwawāʻenakaulua, roughly “two celestial bodies of unfathomable darkness” surrounded by brilliant energy.
The search began with a familiar object. Astronomers had known the brighter quasar for more than two decades. While examining data from the James Webb Space Telescope’s Aether survey, which studied 200 distant quasars, they noticed a much fainter companion nearby.
The team turned to the Gemini North telescope on Maunakea in Hawaiʻi. Separating the sources from the ground was exceptionally difficult. They appeared less than one arcsecond apart, a tiny angular measure of their separation on the sky, and one source was substantially fainter than the other.
Clear conditions made the observations possible. Onorato said: “The sky over Maunakea was so clean and sharp that we managed to collect the data in only two nights.”
The team split the light from each source into its constituent wavelengths, producing spectra, or patterns of light that reveal the motion of gas around the apparent black holes. The observations yielded two quasar spectra at almost exactly the same cosmic distance.
Could gravitational lensing explain the pair?
An intervening galaxy could still mimic the pair. Gravity can bend background light and make one distant object appear as two, an effect called gravitational lensing. The researchers cannot yet completely rule out that possibility.
Subtle differences between the spectra favor two distinct quasars rather than a lensed image of one. Further analysis will be needed to settle the question, leaving Nāpōwawāʻenakaulua as a candidate pair rather than a confirmed system.
How could black holes grow so massive so quickly?
Black holes grow by swallowing gas and sometimes merging with other black holes. Both processes take time, and the universe’s first 900 million years offered little of it.
Several explanations could produce such masses. Some black holes may have formed through the direct collapse of enormous gas clouds rather than the deaths of ordinary stars. Others may have experienced prolonged periods of exceptionally rapid feeding.
Both apparent quasars consume matter at around the Eddington limit, the point at which outward radiation pressure from infalling gas roughly balances the gravitational pull drawing that gas inward. In other words, each feeds at about the maximum rate allowed by current models.
What does the crowded neighborhood imply?
The close pair raises a second puzzle. Finding such a compact pair in the Aether survey implies a concentration of quasars on these small scales roughly 100 to 1,000 times higher than expected from extrapolating existing measurements of how distant quasars cluster.
The discrepancy is striking, although the estimate depends heavily on a single candidate and on the assumptions used for comparison. The figure remains a clue to test, not a settled measurement of early quasar clustering.
If genuine, the pair could point toward the dense environments where some of the first giant galaxies took shape. Rather than overturning models of black hole growth, it would offer a rare test of those models in one of the most extreme environments yet observed.
via zmescience.com (Source)
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Senior reporter covering people, launches and day-to-day practice in general science news at SciBeat.
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