A record-breaking explosion created by a black hole 390 million light-years away has been discovered by astronomers.
“In some ways, this blast is similar to how the eruption of Mt. St. Helens in 1980 ripped off the top of the mountain,” said Simona Giacintucci, lead study author at the Naval Research Laboratory in Washington, D.C.
“A key difference is that you could fit 15 Milky Way galaxies in a row into the crater this eruption punched into the cluster’s hot gas,” Giacintucci said.
Supermassive Black Hole
The explosion originated from the center of the Ophiuchus galaxy cluster. Clusters of galaxies are the largest-known structures in the universe.
Astronomers believe a supermassive black hole at the heart of a large galaxy toward the center of the cluster is responsible for the explosion.
Black holes don’t just gobble up material, they blast it out as well—usually in the form of jets or beams of material.
And this one breaks all previous records. The energy that created the explosion was five times greater than MS 0735+74, once known as the largest and most powerful explosion.
Astronomers made the observation using ground and space-based telescopes, including NASA’s Chandra X-ray Observatory, the European Space Agency’s XMM-Newton X-ray space observatory, Australia’s Murchison Widefield Array, and the Giant Metrewave Radio Telescope in India.
A Hint Years Ago
There was an earlier hint suggesting activity around this current event in 2016, when observations made using Chandra revealed a possible explosion in the galactic cluster.
In 2016, astronomer Norbert Werner and his colleagues noticed that there appeared to be a cavity in hot gas created by the black hole’s jets. But the cavity was so large and would have required so much energy to form that they didn’t think it was possible.
The new study, published Thursday in The Astrophysical Journal, reveals the explosion and confirms the cavity initially detected in 2016.
“I was really happy when I saw these results,” Werner commented in a blog post on the Chandra site. “In our paper we considered the possibility that the feature is a result of a record-breaking black hole outburst, but we discounted it as unlikely.”
“This is one of the nearest galaxy clusters and it appeared to be too much of a coincidence to see such an outburst in our cosmic backyard,” Werner wrote. “Extraordinary claims need extraordinary evidence and the observation reported in this paper provides the evidence that we lacked.”
The X-ray data, combined with radio wavelength data by the ground-based telescopes, helped confirm the cavity because it bordered a radio emission-filled region. Those radio emissions were created by electrons moving at the speed of light in the jets moving away from the black hole.
“The radio data fit inside the X-rays like a hand in a glove,” said study co-author Maxim Markevitch, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This is the clincher that tells us an eruption of unprecedented size occurred here.”
‘Like Discovering a Dinosaur’
The explosion has since ceased because current radio data don’t reveal any jet activity. Chandra was perfectly suited for this detection because it can spy cool, dense gas through X-rays, which would otherwise be invisible.
That gas has moved on from the black hole and galaxy, essentially cutting off the fuel for the black hole to create jets.
“This has been like discovering a dinosaur, with just a little piece (the unusual X-ray edge) sticking out at first and then suddenly a new kind of creature coming out from the ground,” wrote Giacintucci and Markevitch in a blog post on the Chandra site.
But radio emissions are missing on the other side of the black hole, creating a mystery for astronomers to solve. Typically, jets blast out on both sides of the black hole.
“As is often the case in astrophysics we really need multiwavelength observations to truly understand the physical processes at work,” said study co-author Melanie Johnston-Hollitt, Director of the Murchison Widefield Array and astrophysicist at the International Center for Radio Astronomy in Australia.
“Having the combined information from X-ray and radio telescopes has revealed this extraordinary source, but more data will be needed to answer the many remaining questions this object poses.”