An international collaboration co-led by an IAS scholar has uncovered a universal rule governing one of the most powerful astronomical events in the universe: the launching of jets by black holes . The team has shown that black holes—whether they are "stellar-mass" objects ten times the mass of our sun or supermassive giants millions of times heavier—fire powerful jets of material at the exact same critical juncture in their feeding cycles.
The groundbreaking work was authored by Andrew Mummery , Martin A. and Helen Chooljian Member (2025–30) in the School of Natural Sciences , alongside Adelle Goodwin, a Forrest Research Foundation Fellow at Curtin University's International Centre of Radio Astronomy Research in Western Australia.
Published in Nature Astronomy under the title "A universal critical accretion rate for black hole jet formation," the research represents the culmination of years of analysis, piecing together multi-wavelength observations from telescopes positioned across the globe, including facilities in America, Australia, India, South Africa, and space. The team tracked tidal disruption events —where stars are torn apart by the immense gravitational forces of supermassive black holes—allowing researchers to observe exactly what happens in the aftermath.
"We really wanted to figure out this massive puzzle," said Mummery. "Why do some supermassive black holes blast out radio jets right after shredding a star, while others just sit there looking completely dormant, only to suddenly fire up their jets months or even years later?" Black holes are frequently described as cosmic vacuum cleaners, but they are far more accurately described as messy eaters. "When a black hole tears apart a star, it does not swallow everything neatly," Goodwin stated. While a portion is consumed, much is violently launched back into space in powerful outflows. These immense cosmic "burps" can blast material across staggering distances, fundamentally influencing the evolution of their host galaxies.
For decades, astrophysicists have suspected that black holes follow the same basic laws of physics regardless of their immense variations in size. Proving this has historically been difficult because supermassive black holes typically evolve over thousands or millions of years. By focusing on tidal disruption events, the team bypassed this limitation. These events compress a supermassive black hole's feeding episode into a timeframe of mere years, granting researchers like Mummery and Goodwin a unique window into the dynamic process as it unfolds.
The pivotal moment of realization for the team occurred not while trawling through telescope data, but in a bar in Madrid during an astrophysics conference. It was there that Mummery and Goodwin realized the same underlying rule dictating jet launches in small black holes appeared to universally apply to supermassive ones.
To confirm this, they meticulously analyzed twenty tidal disruption events using optical, ultraviolet, X-ray, and radio observations, narrowing their sample to ten high-quality events where they could reliably model both the feeding rate and the timing of radio outflows. The analysis revealed two distinct jet-launching phases. The first happens early, when the black hole is feeding at extreme rates. The second comes much later, hundreds to thousands of days after the star is first torn apart, when the black hole's feeding rate drops to about two percent of its Eddington limit—the point at which outward radiation pressure balances gravity. The same two percent threshold is already known to trigger jet formation in much smaller black holes in our galaxy, demonstrating that this fundamental piece of black hole physics scales universally.
Beyond solving this mystery, Mummery and Goodwin's findings offer highly practical benefits for astronomy. By understanding precisely when a black hole is most likely to launch a delayed jet, astronomers can better anticipate these events. This predictive power allows the scientific community to optimize the use of highly in-demand instruments worldwide. Targeted campaigns can be run with greater efficiency, ensuring fewer wasted observations and improving the chances of capturing fleeting events across major facilities, such as the Square Kilometre Array radio telescope project, which is poised to begin collecting scientific data in 2028. "We hope that our work will pave the way for even more profound discoveries about our universe," said Mummery.
About the Institute
The Institute for Advanced Study has served as one of the leading independent centers for theoretical research and intellectual inquiry since its establishment in 1930, advancing the frontiers of knowledge across the sciences and humanities. From founding IAS Faculty Albert Einstein, Erwin Panofsky, and John von Neumann to influential figures Emmy Noether, George Kennan, and J. Robert Oppenheimer to the foremost thinkers of the present, IAS is dedicated to enabling independent inquiry and fundamental discovery.
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