In 2019, the first ever direct image of a black hole was a hazy, orange revelation. Now, the same team of researchers has produced an update of that image that renders the swirling arcs of the supermassive black hole’s magnetic fields, reports Daniel Clery for Science.
The spruced-up picture released by the team of more than 300 researchers behind the Event Horizon Telescope collaboration unveiled the spiraling lines of magnetism emanating from the shadowy center of the black hole by polarizing the light of the first image.
Revealing the structure of the M87 black hole’s magnetic fields may help explain how the celestial vacuum sucks down matter as well as how it fires powerful jets of plasma many thousands of light-years into space, reports Maria Temming for Science News.
“We are now seeing the next crucial piece of evidence to understand how magnetic fields behave around black holes, and how activity in this very compact region of space can drive powerful jets that extend far beyond the galaxy,” says Monika Mościbrodzka, an astrophysicist at Radboud Universiteit in the Netherlands and a coordinator of the working group behind the new research, in a statement.
Getting the data necessary to polarize the image was not as simple as slapping new lens filters on the eight observatories used to capture the initial image of the black hole anchored in the center of the M87 galaxy. Adding polarization took years of extracting and analyzing new strands from the trove of data used to create the 2019 image.
Along with the image itself, the Event Horizon Telescope (EHT) collaboration published a pair of papers today that detail the litany of methodologies and findings undergirding the picture in the journal Astrophysical Journal Letters.
"In order to gain confidence in our analysis, we used as many as five distinct methods to calibrate the data and reconstruct polarimetric images," says Maciek Wielgus, an astrophysicist at Harvard-Smithsonian Center for Astrophysics and one of the study’s co-authors, in a statement.
Per Science News, the significance of polarizing the image is that polarization measures the orientation of light waves, showing whether they’re oscillating vertically, horizontally or diagonally. The significance of polarization to magnetism is that magnetic fields can alter light’s orientation, allowing polarized light to serve as a kind of roadmap for the structure of any magnetic fields it passes through.
In the statement, Iván Martí-Vidal, an astronomer at the University of València in Spain who also helped coordinate the working group behind the research, says illuminating the black hole with polarized light provides valuable information about the black hole’s physics that allows researchers to better understand the image initially produced in 2019. In particular, researchers say the polarized image may help explain the origins of powerful jets of plasma produced by black holes.
“We’ve known for decades that jets are in some sense powered by accretion onto supermassive black holes, and that the in-spiraling gas and the outflowing plasma are highly magnetized—but there was a lot of uncertainty in the exact details,” Eileen Meyer, an astrophysicist at the University of Maryland who was not involved in the work, tells Science News. “The magnetic field structure of the plasma near the event horizon [of a black hole] is a completely new piece of information.”
The image reveals that the magnetic fields of this supermassive black hole are well-ordered, Sara Issaoun, an astronomer at Radboud University in the Netherlands, tells Leah Crane of New Scientist. “This is really important because only an ordered magnetic field can launch jets—a scrambled magnetic field cannot do that,” Issaoun tells New Scientist.
According to Science, the M87 black hole has a jet that stretches 5,000 light-years beyond the galaxy, and the structure of the black hole’s magnetic fields suggests magnetism may play a role in funneling matter out towards the jet, somehow overpowering the gravitational suck of a black hole 6.5 billion times the mass of the sun.