Star’s Destruction by Supermassive Black Hole Linked to Origin of Universe’s Highest-Energy Particles

A team of scientists has detected the presence of a high-energy neutrino—a particularly elusive particle—in the wake of a star’s destruction as it is consumed by a black hole. A team of scientists has detected the presence of a high-energy neutrino—a particularly elusive particle—in the wake of a star’s destruction as it is consumed by a black hole. This discovery, reported in the journal Nature Astronomy, sheds new light on the origins of Ultrahigh Energy Cosmic Rays—the highest energy particles in the Universe. The work, which included researchers from more than two dozen institutions, including New York University and Germany’s DESY research center, focused on neutrinos—subatomic particles that are produced on Earth only in powerful accelerators. Neutrinos—as well as the process of their creation—are hard to detect, making their discovery, along with that of Ultrahigh Energy Cosmic Rays (UHECRs), noteworthy. “The origin of cosmic high-energy neutrinos is unknown, primarily because they are notoriously hard to pin down,” explains Sjoert van Velzen, one of the paper’s lead authors and a postdoctoral fellow in NYU’s Department of Physics at the time of the discovery. “This result would be only the second time high-energy neutrinos have been traced back to their source.”

A view of the accretion disc around the supermassive black hole, with jet-like structures flowing away from the disc. The extreme mass of the black hole bends spacetime, allowing the far side of the accretion disc to be seen as an image above and below the black hole. Credit: DESY, Science Communication Lab

The following video, created by NASA, a research partner on the Nature Astronomy work, describes the findings in greater detail (video credit: NASA’s Goddard Space Flight Center).

Previous research by van Velzen, now at the Netherlands’ Leiden University, and NYU physicist Glennys Farrar, a co-author of the new Nature Astronomy paper, found some of the earliest evidence of black holes destroying stars in what are now known as Tidal Disruption Events (TDEs). These findings set the stage for determining if TDEs could be responsible for producing UHECRs.

The research reported in Nature Astronomy offered support for this conclusion.

Previously, the IceCube Neutrino Observatory, a National Science Foundation-backed detector located in the South Pole, reported the detection of a neutrino, whose path was later traced by the Zwicky Transient Facility at Caltech’s Palomar Observatory.

Specifically, its measurements showed a spatial coincidence of a high-energy neutrino and light emitted after a TDE—a star consumed by a black hole.

“This suggests these star shredding events are powerful enough to accelerate high-energy particles,” van Velzen explains.

“Discovering neutrinos associated with TDEs is a breakthrough in understanding the origin of the high-energy astrophysical neutrinos identified by the IceCube detector at the South Pole whose sources have so far been elusive,” adds Farrar, who proposed in a 2009 paper that UHECRs could be accelerated in TDEs. “The neutrino-TDE coincidence also sheds light on a decades old problem: the origin of Ultrahigh Energy Cosmic Rays.”

After the supermassive black hole tore the star apart, roughly half of the star debris was flung back out into space, while the remainder formed a glowing accretion disc around the black hole. The system shone brightly across many wavelengths and is thought to have produced energetic, jet-like outflows perpendicular to the accretion disc. A central, powerful engine near the accretion disc spewed out these fast subatomic particles. Credit: DESY, Science Communication Lab

Read Ghost Particle From Star Shredded by Black Hole Reveals Cosmic Particle Accelerator for more on this research.

Reference: “A tidal disruption event coincident with a high-energy neutrino” by Robert Stein, Sjoert van Velzen, Marek Kowalski, Anna Franckowiak, Suvi Gezari, James C. A. Miller-Jones, Sara Frederick, Itai Sfaradi, Michael F. Bietenholz, Assaf Horesh, Rob Fender, Simone Garrappa, Tomás Ahumada, Igor Andreoni, Justin Belicki, Eric C. Bellm, Markus Böttcher, Valery Brinnel, Rick Burruss, S. Bradley Cenko, Michael W. Coughlin, Virginia Cunningham, Andrew Drake, Glennys R. Farrar, Michael Feeney, Ryan J. Foley, Avishay Gal-Yam, V. Zach Golkhou, Ariel Goobar, Matthew J. Graham, Erica Hammerstein, George Helou, Tiara Hung, Mansi M. Kasliwal, Charles D. Kilpatrick, Albert K. H. Kong, Thomas Kupfer, Russ R. Laher, Ashish A. Mahabal, Frank J. Masci, Jannis Necker, Jakob Nordin, Daniel A. Perley, Mickael Rigault, Simeon Reusch, Hector Rodriguez, César Rojas-Bravo, Ben Rusholme, David L. Shupe, Leo P. Singer, Jesper Sollerman, Maayane T. Soumagnac, Daniel Stern, Kirsty Taggart, Jakob van Santen, Charlotte Ward, Patrick Woudt and Yuhan Yao, 22 February 2021, Nature Astronomy.
DOI: 10.1038/s41550-020-01295-8

The research was supported by grants from the National Science Foundation (CAREER grant 1454816, AAG grant 1616566, PIRE Grant 1545949, NSF grant AST-1518052)

Astronomers detect biggest explosion in the history of the Universe

Scientists studying a distant galaxy cluster have discovered the biggest explosion seen in the Universe since the Big Bang. The blast came from a supermassive black hole at the centre of a galaxy hundreds of millions of light-years away. It released five times more energy than the previous record holder. Professor Melanie Johnston-Hollitt, from the Curtin University node of the International Centre for Radio Astronomy Research, said the event was extraordinarily energetic. "We've seen outbursts in the centres of galaxies before but this one is really, really massive," she said. "And we don't know why it's so big. "But it happened very slowly--like an explosion in slow motion that took place over hundreds of millions of years." The explosion occurred in the Ophiuchus galaxy cluster, about 390 million light-years from Earth. It was so powerful it punched a cavity in the cluster plasma--the super-hot gas surrounding the black hole. Lead author of the study Dr Simona Giacintucci, from the Naval Research Laboratory in the United States, said the blast was similar to the 1980 eruption of Mount St. Helens, which ripped the top off the mountain. "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," she said. Professor Johnston-Hollitt said the cavity in the cluster plasma had been seen previously with X-ray telescopes. But scientists initially dismissed the idea that it could have been caused by an energetic outburst, because it would have been too big.

"People were sceptical because the size of outburst," she said. "But it really is that. The Universe is a weird place."

The researchers only realised what they had discovered when they looked at the Ophiuchus galaxy cluster with radio telescopes.

"The radio data fit inside the X-rays like a hand in a glove," said co-author Dr Maxim Markevitch, from NASA's Goddard Space Flight Center.

"This is the clincher that tells us an eruption of unprecedented size occurred here."

The discovery was made using four telescopes; NASA's Chandra X-ray Observatory, ESA's XMM-Newton, the Murchison Widefield Array (MWA) in Western Australia and the Giant Metrewave Radio Telescope (GMRT) in India.

Professor Johnston-Hollitt, who is the director of the MWA and an expert in galaxy clusters, likened the finding to discovering the first dinosaur bones.

"It's a bit like archaeology," she said.

"We've been given the tools to dig deeper with low frequency radio telescopes so we should be able to find more outbursts like this now."

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," she said.

Professor Johnston-Hollitt said the finding is likely to be the first of many.

"We made this discovery with Phase 1 of the MWA, when the telescope had 2048 antennas pointed towards the sky," she said. "We're soon going to be gathering observations with 4096 antennas, which should be ten times more sensitive."

"I think that's pretty exciting."