The telescope that captured the first-ever image of a supermassive black hole at the center of the Messier 87 galaxy has produced a new image, this time depicting the black hole in polarized light. The view is crucial to helping astronomers understand how M87—55 million light-years away from Earth—is able to launch energetic jets from its core and “eat” surrounding matter.
The jets, which extend at least 5,000 light-years, are one of the galaxy’s most captivating features.
A view of the M87 supermassive black hole in polarized light. Courtesy of EHT Collaboration
The new image taken by the Event Horizon Telescope (EHT), a collaboration linking eight telescopes around the world, represents the first time astronomers have been able to measure light polarization so close to the edge of a black hole. This polarization signifies the presence of magnetic fields at the juncture where matter flows in or is ejected out.
“You can see the orientation of these light waves highlighted in elegant golden arcs around the black hole’s shadow,” said EHT researchers, sharing the image on Facebook.
Black holes, they explained, have the strongest gravitational pull in the universe. They bend the path of light, pull blazing-hot plasma into orbit, and warp magnetic fields. Some shoot out powerful jets of matter at phenomenal speeds.
A composite image showing three views of the central region of the M87 galaxy in polarized light. (Courtesy of EHT Collaboration; ALMA (ESO/NAOJ/NRAO), Goddi et al.; VLBA (NRAO), Kravchenko et al.; J.C. Algaba, I. Martí-Vidal)
“But why do these jets form, and how do they resist the pull of the black hole?” they posed. “With this breakthrough, EHT scientists have taken a crucial step in solving the mystery.”
Data on the M87 galaxy’s supermassive black hole, which is 6.5 billion times more massive than our sun, has been collected since 2017. The first-ever image of the black hole was released on April 10, 2019, depicting a bright ring-like structure with a dark shadow at the center.
EHT project director Sheperd S. Doeleman, of the Harvard & Smithsonian Center for Astrophysics, hailed the image as “something presumed to be impossible just a generation ago.”
Light becomes polarized when emitted in hot regions of magnetized space. The significant polarized light around the M87 black hole offers astronomers clarity to map magnetic field lines and examine exactly how some matter escapes at the event horizon, or “point of no return,” to be blown into space in the form of jets.
“The main finding is that we not only see the magnetic fields near the black hole as expected, but they also appear to be strong,” Jason Dexter, of the University of Colorado Boulder, and coordinator of the EHT Theory Working Group, told Space.com.
“Our results indicate that the magnetic fields can push the gas around and resist being stretched,” he explained. “The result is an interesting clue to how black holes feed on gas and grow.”
The jets of energy produced are collimated, meaning they maintain a consistent shape over huge distances. Coupled to the black hole, its magnetic field controls how the jets of matter flow, study co-author Dr. Ziri Younsi, of University College London, explained to MailOnline.
“Before we had no idea, it was very speculative,” Younsi said, “but now we have very strong evidence to indicate how the magnetic field is organized … it is very organized, very structured, which is surprising.”
The EHT collaboration of eight ground-based radio telescopes, positioned at high-altitude sites, created a virtual Earth-sized telescope. The culmination of decades of work, its combined resolution is capable of measuring the length of a credit card on the surface of the Moon.
(Courtesy of ESO/L. Calçada, Digitized Sky Survey 2, ESA/Hubble, RadioAstron, De Gasperin et al., Kim et al., EHT Collaboration. Music: Niklas Falcke)
EHT’s latest findings on the M87 supermassive black hole, supported by 300 researchers from organizations and universities around the world, were published in The Astrophysical Journal Letters on March 24.
The team’s next major project is to publish an image of the black hole at the center of the Milky Way, Sagittarius A*, said Younsi. While less static, this black hole is 1,000 times closer, and also 1,000 times smaller, than M87.
