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Space·2 min read

Nāpōwawāʻenakaulua: Webb Finds Earliest Quasar Pair Ever

Webb has spotted two quasars just 18,100 light-years apart, seen 900 million years after the Big Bang. Both black holes are far bigger than models allow.

Artist's illustration of two glowing quasars, each powered by a supermassive black hole, orbiting close together in the early universe.
Image: Space
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Two giant black holes, glowing fiercely, sitting close together in a universe that was barely 900 million years old. Astronomers using the James Webb Space Telescope (JWST) have found the oldest quasar pair ever seen, and by current theory it shouldn't exist.

The pair is called J1602+4228AB. Its nickname is Nāpōwawāʻenakaulua, a Hawaiian name that means "Two celestial bodies of fathomless powerful darkness in the brilliance of heat reincarnating energy into the universe." The two supermassive black holes weigh 1.5 billion and 400 million times the mass of the sun. They sit only 18,100 light-years apart, about one-fifth the width of the Milky Way. That makes this the most compact quasar pair found from Cosmic Dawn, the era just after the first stars, galaxies and black holes appeared.

What is a quasar, and why is this pair a problem?

A quasar is a supermassive black hole surrounded by a flat, swirling disk of gas and dust. Gravity-driven friction heats the disk until it can outshine every star in the galaxy around it.

Current models say black holes need at least a billion years to feed and merge their way to millions or billions of solar masses. Webb has been finding massive ones as early as 400 million years after the Big Bang, and this pair makes the puzzle worse. "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 team leader Silvia Onorato of NOIRLab. Its black holes are "just as massive as those we see today."

How was it found?

The team spotted it in data from Webb's Aether survey, a census of the early universe. Using the NIRSpec instrument, Aether has turned up 200 quasars, just under half of all known early-universe quasars. While browsing the data, the team saw that J1602+4228A had a companion, now called J1602+4228B.

Splitting two objects this close from the ground should have been nearly impossible. Gemini North managed it thanks to perfect timing and perfect weather over Maunakea, the dormant volcano on Hawai'i where it sits.

The mystery is still open. Onorato calls the system "a laboratory" for studying how the first massive galaxies and their central black holes came together through direct galaxy interactions. The results appeared on Tuesday (Nov. 10) in The Astrophysical Journal Letters.

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Tags:james webb space telescopequasarblack holescosmic dawngemini northnoirlab

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