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Using the James Webb Space Telescope (JWST), astronomers have discovered the oldest pair of supermassive black hole-powered quasars ever seen. There’s just one problem: they shouldn’t exist!
The compact quasar pair, spotted with the aid of the Gemini North telescope, has been designated J1602+4228AB and nicknamed Nāpōwawāʻenakaulua, which means “Two celestial bodies of fathomless powerful darkness in the brilliance of heat reincarnating energy into the universe.” The compact quasar pair is seen as it was 900 million years after the Big Bang at a time when such supermassive black holes should not have had time to grow to such tremendous masses.
Nāpōwawāʻenakaulua isn’t just the oldest and most distant quasar pairing ever seen. There is just 18,100 light-years, or roughly one-fifth the diameter of the Milky Way, between the supermassive black holes, which have masses of 1.5 billion and 400 million times that of the sun. That makes Nāpōwawāʻenakaulua the most compact quasar pair found during a period of the universe’s history known as Cosmic Dawn, shortly after the birth of the first stars, galaxies, and black holes.
“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,” research team leader Silvia Onorato of the NOIRLab said in a statement.
“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.”
How were supermassive black holes over fed at Cosmic Dawn
Quasars occur when the supermassive black holes that sit at the heart of large galaxies are surrounded by a flattened cloud of swirling gas and dust called an “accretion disk,” from which they feed or “accrete” matter. The immense gravity of the central black hole causes friction, heating the accretion disk and causing it to glow, often brighter than the combined light of every star in the surrounding galaxy. We see that glow as a quasar.
Finding such objects in the recent cosmic history of the 13.8-billion-year-old universe isn’t troubling, though finding compact pairs of them is still extremely rare. Such pairs should be common because the merger of galaxies that brings together supermassive black holes is frequent. That should lead to an abundance of pairs of quasars with a separation less than the typical size of a galaxy.
There are three reasons this has proven tricky. Firstly, the “quasar phase” of a supermassive black hole is relatively short on cosmic terms. Secondly, even relatively close quasar pairs are very far away, making them faint and hard to detect with ground-based telescopes. Finally, at such great distances and with such a small separation between the two supermassive black holes, the individual members of a quasar pair are hard to individually resolve.
Yet, astronomers do find quasar pairs. Sometimes at distances and times that they would probably rather not, because it challenges everything we know about black hole growth.
The trouble arises before the universe was 1 billion years. That is because, according to current models, black holes should need at least 1 billion years to feed and merge enough to reach masses millions or billions of times that of the sun.
Yet, since it began operations in 2022, the JWST has been routinely discovering supermassive black holes powering quasars as early as 400 million years after the Big Bang. If that wasn’t confusing enough, the discovery of Nāpōwawāʻenakaulua, the third quasar pair seen at Cosmic Dawn, could really break current models.
Nāpōwawāʻenakaulua was uncovered in data from the JWST’s Aether survey, which is conducting a census of objects in the early universe. Using JWST’s NIRSpec (Near-Infrared Spectrograph Integral Field Unit) instrument, the survey has uncovered 200 quasars, just under half of all currently known early universe quasars. It was while browsing the Aether dataset that the team discovered that quasar J1602+4228A is not alone, it had a companion now designated J1602+4228B.
Resolving these two quasars should have been nearly impossible from the ground. But this was possible for Gemini North thanks to perfect timing and perfect weather conditions over Maunakea, the dormant volcano on the island of Hawai’i where the telescope is located.
A definite scientific feat, Nāpōwawāʻenakaulua remains a mystery for now, but it could actually help scientists better understand how galaxies were coming together during Cosmic Dawn, a vital stage in the evolution of the universe.
“Nāpōwawāʻenakaulua is a really unique environment,” Onorato said. “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.”
The team’s results were published on Tuesday (Nov. 10) The Astrophysical Journal Letters.
