Princeton astrophysicists unravel the mystery of black hole jets and galactic 'light sabers'

A team of astrophysicists at Princeton University has been able to conclusively determine that the energy is close to that Black hole M87* pushes outward, not inward, which is a long-standing debate within the field.

The one thing everyone knows about black holes is that everything near them gets sucked into them.

barely Everything, it turns out.

Elliot Quataert, astrophysicist and Charles A. Young Professor of Astronomy at Princeton University: “Although black holes are known as objects from which nothing can escape, one of the startling predictions of Einstein's theory of relativity is that black holes can actually lose energy.” Batch from the 1897 Foundation. “It can spin, and just as a spinning top slows down over time and loses that energy as it spins, a rotating black hole can also lose energy to its surroundings.”

This model has been widely accepted by scholars since the 1970s. They knew that magnetic fields might extract energy from rotating black holes, but they didn't know how.

A team of astrophysicists at Princeton University has conclusively determined that energy near the event horizon of black hole M87* is rushing outward, not inward. (M87 is the name of the galaxy, Messier 87, so the black hole at its center is called M87*.) Quatert said the researchers also devised a way to test the prediction that black holes lose rotational energy, and to prove it is that energy that produces the “incredibly powerful outflows.” That we see and that we call jets.”

An animation showing how the magnetic field crossing the black hole's event horizon is twisted as the black hole spins faster. A faster-spinning black hole spins the magnetic field more quickly, causing the black hole to lose more energy to its surroundings. A team of astrophysicists at Princeton University observed wrapping magnetic field lines in images from the Event Horizon Telescope of linear polarization of black holes. Credit: Video by George Wong, Institute for Advanced Study Princeton University

These jets of energy flow are “basically like a million-Light year“Long lightsabers can extend 10 times longer than a Jedi lightsaber,” says Alexandru Lobsaska, a former postdoctoral researcher at Princeton University. milky way galaxy.

The results of their work were recently published in the Astrophysical Journal. Andrew Chell, a research associate in astrophysics, is the first author of this paper. He and co-author George Wong are both members of Event horizon telescope They played a crucial role in developing the models used to explain black holes. Chael, Wong, Lobsaska, and Quataert are all theorists affiliated with Princeton Gravity Initiative.

The team credited Schell with the vital insight at the heart of the new paper: that the direction in which magnetic field lines ascend reveals the direction of energy flow. From there, “the rest fell into place,” Quataert said.

The black hole M87* (the star sign of the black hole at the center of the galaxy M87) captured the world's attention when it was first discovered by the Event Horizon Telescope. Since then, astrophysicists at Princeton University have discovered that the twisting magnetic field around the black hole determines the polarization vortex observed in images of the black hole. In particular, the direction of the energy flow (from hole to field or vice versa) determines how the polarization is wrapped. By measuring the direction in which the polarization twists, one can infer whether the magnetic field is extracting spin energy from the hole or injecting spin energy into it. Image source: Model by Andrew Chell, George Wong, Alexandru Lobsaska, and Elliot Quataert, Princeton Gravity Initiative

“If you took the Earth and turned it all into TNT and blew it up 1,000 times a second for millions and millions of years, that's the amount of energy we'd get out of M87,” said Wong, a research associate at Harvard University. Princeton Gravity Initiative and a member of the Institute for Advanced Study.

Scientists have known for decades that when a black hole begins to spin, it pulls the fabric of space-time with it. The magnetic field lines passing through the black hole are pulled, slowing the rotation, releasing energy.

“Our new, sharp prediction is that whenever you look at an astrophysical black hole, if it has magnetic field lines attached to it, there will be energy transfer — really crazy amounts of energy transfer,” said Lobsaska, a former research associate at UCLA. Princeton and is now an assistant professor of physics and mathematics at Vanderbilt University, for which he won an award 2024 New Frontiers in Physics Prize From the Foundation Breakthrough Award for his research on black holes.

While the energy flow near M87*'s event horizon is directed outward, the team said the energy flow could theoretically be directed inward into a different black hole. They are confident of their connection between the flow of energy and the direction of the magnetic field lines, and their prediction that the flow of energy comes from the black hole will be tested with the launch of the “still theoretical”next generation“Event Horizon Telescope.

For the past year and a half, black hole researchers around the world have been proposing specifications for the future instrument, Wong said. “Research papers like ours can play a crucial role in determining what we need. I think this is a very exciting time.”

The four researchers stressed in their paper that they have not shown conclusively that the black hole's rotation “actually powers extragalactic jets,” although the evidence certainly leans in that direction. Although the power levels shown by their model are consistent with what aircraft need, they cannot rule out the possibility of the aircraft being powered by a spin. plasma Outside the black hole. “I think it's very likely that the black hole is the power source for the plane, but we can't prove that,” Lobsaška said. “Until now.”

Reference: “Measurement of Black Hole Polarization I. Signature of Electromagnetic Energy Extraction” by Andrew Chell, Alexandru Lobsaska, and George N. Wong, Elliot Quataert, November 14, 2023, Astrophysical Journal.
doi: 10.3847/1538-4357/acf92d

This research was supported by the Princeton Gravity Initiative, a Taplin Fellowship, the National Science Foundation (Grant No. 2307888) and a Simons Foundation Investigator Award.