Using data from ESA’s XMM-Newton and NASA’s Chandra X-ray space observatories, along with two ground-based radio telescopes in Australia and India, astronomers have spotted the aftermath of the most powerful explosion ever seen in the Universe. The huge outburst occurred in the Ophiuchus galaxy cluster, a group of thousands of galaxies some 390 million light years away. The explosion is about five times greater than the previous record holder, observed in the galaxy cluster MS 0735.6+7421, and hundreds and thousands of times greater than typical clusters.
Evidence for the biggest black hole eruption seen in the Universe comes from a combination of X-ray data from Chandra and XMM-Newton, and the Murchison Widefield Array and Giant Metrewave Telescope, as shown here. The eruption is generated by a black hole located in the central galaxy of the Ophiuchus galaxy cluster, which has blasted out jets and carved a large cavity in the surrounding hot gas. Image credit: NASA / CXC / NRL / S. Giacintucci et al / ESA / XMM-Newton / NCRA / TIFR / GMRT / 2MASS / UMass / IPAC-Caltech / NSF.
“The event was extraordinarily energetic. We’ve seen outbursts in the centers of galaxies before but this one is really, really massive. And we don’t know why it’s so big,” said Professor Melanie Johnston-Hollitt, an astronomer in the Curtin University node of the International Centre for Radio Astronomy Research.
“But it happened very slowly — like an explosion in slow motion that took place over hundreds of millions of years.”
In 2016, a team of astronomers had found first hints of the giant explosion in the Chandra data, reporting the discovery of an unusual curved edge in the X-ray image of the Ophiuchus galaxy cluster.
They considered whether this edge might point to a cavity in the hot gas linked to the black hole jets, but discarded the possibility at the time.
In the new study, Professor Johnston-Hollitt and colleagues detected the curved edge also in XMM-Newton data, confirming the earlier Chandra observation.
The researchers combined the X-ray data with radio wave observations of the Ophiuchus cluster from the Murchison Widefield Array (MWA) in Australia and the Giant Metrewave Radio Telescope (GMRT) in India, revealing that the curved edge delimits a region filled with radio-emitting gas and is indeed part of the wall of a cavity in the hot gas.
“People were skeptical because the size of outburst,” Professor Johnston-Hollitt said.
“But it really is that. The Universe is a weird place.”
“The radio data fit inside the X-rays like a hand in a glove. This is the clincher that tells us an eruption of unprecedented size occurred here,” said Dr. Maxim Markevitch, from NASA’s Goddard Space Flight Center.
The black hole eruption released an amount of energy about five times greater than that involved in the most powerful event of this type known to date, MS0735.6+7421.
“The 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,” said Dr. Simona Giacintucci, an astronomer in the U.S. Naval Research Laboratory.
“The finding underscores the importance of studying the Universe at different wavelengths,” Professor Johnston-Hollitt said.
“Going back and doing a multi-wavelength study has really made the difference here.”
The discovery is reported in a paper in the Astrophysical Journal.
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S. Giacintucci et al. 2020. Discovery of a Giant Radio Fossil in the Ophiuchus Galaxy Cluster. ApJ 891, 1; doi: 10.3847/1538-4357/ab6a9d
