XRISM Reveals Black Hole Winds Are 100 Times More Powerful Than Expected

Black holes are mostly known for pulling matter in. But they also push enormous amounts of energy outward, and new observations suggest those outflows are far more powerful than anyone realised.

A team led by Satoshi Yamada at Tohoku University used the XRISM X-ray astronomy satellite, a joint mission between JAXA and NASA, to study a quasar called H1821+643. It sits in the constellation Draco, roughly 3.4 billion light-years from Earth. What they found is that the winds driven by the supermassive black hole at its centre carry about 100 times more energy than earlier estimates suggested.

That is a significant revision. Previous models treated black hole winds as something that affected the immediate neighbourhood of the host galaxy. This study, published in Nature Astronomy under the title "Vigorous turbulence driven by quasar-mode feedback in a cluster core," shows the turbulence extends roughly 300,000 light-years outward. To put that in context, the Milky Way itself is about 100,000 light-years across. These winds are reaching well beyond the galaxy that hosts the black hole and into the surrounding galaxy cluster.

The energy involved is staggering. The researchers describe it as comparable to the combined output of several billion supernova explosions. That is not a comparison made lightly; supernovae are among the most energetic events in the universe, and here we are talking about billions of them as a rough equivalent for the sustained turbulence driven by a single quasar.

XRISM made this possible because of its ability to measure X-ray emission lines with extremely high precision. The team analysed emission lines from iron ions in the hot gas surrounding H1821+643. Those measurements showed the gas is not sitting still. It is moving violently, with turbulence spreading across the full 300,000 light-year region.

Quasars like H1821+643 are powered by supermassive black holes that are actively consuming gas. As material spirals inward, it releases tremendous energy, making quasars some of the brightest objects in the universe. The key insight from this study is that the energy does not just radiate outward as light. A significant fraction is carried by physical winds that stir and heat the surrounding gas on scales that were previously considered unreachable.

This matters for how we understand galaxy formation and evolution. Astronomers have long known that supermassive black holes influence their host galaxies, a process called feedback. But the standard picture was that this feedback was mostly local. If black hole winds can deposit energy across hundreds of thousands of light-years, they are shaping not just individual galaxies but the larger structures those galaxies sit within.

The practical implication is that models of galaxy cluster evolution will need updating. Simulations that treat black hole feedback as a relatively contained process are probably underestimating its reach. That could help explain some long-standing puzzles about why gas in galaxy clusters does not cool as quickly as simple models predict. If black hole winds are constantly stirring and heating that gas on enormous scales, the slower cooling rate makes more sense.

Yamada put it plainly: "For the first time, we have shown that black holes influence the broader cosmic environment through a shock wave of astonishing power." The team, which included researchers from Kanazawa University and Tokyo Metropolitan University among other institutions, plans to continue using XRISM to map how black holes affect their surroundings across different types of galaxy clusters.

For anyone tracking the XRISM mission, this is exactly the kind of result the satellite was built to deliver. Launched in September 2023 as a replacement for the ill-fated Hitomi satellite, XRISM's high-resolution X-ray spectroscopy is opening up measurements that were simply not possible before. Expect more results like this as the mission continues to observe active galactic nuclei and galaxy clusters.