According to astronomers’ best models of black hole evolution, the magnetic field within the accretion disk must be strong enough to push the accreted plasma out into the surroundings. New results from Sagittarius A*, the 4.3 million solar mass black hole at the center of the Milky Way galaxy, and its much larger cousin M87* provide the first direct observational evidence supporting these models.
This image from the Event Horizon Telescope shows a polarized view of Sagittarius A*. The lines superimposed on this image show the direction of polarization associated with the magnetic field around the black hole’s shadow. Image credit: EHT Collaboration.
In 2022, EHT collaboration The first image of Sagittarius A*, about 27,000 light-years from Earth, has been released, showing that the Milky Way’s supermassive black hole looks very good despite being more than 1/1000th smaller and lighter in mass than M87. revealed that they are similar.
This led scientists to wonder if the two men had more in common than just their looks. To find out, they decided to study Sagittarius A* in polarized light.
Previous studies of the light surrounding M87* revealed that the magnetic field around the supermassive black hole causes powerful jets of matter to be ejected into the surrounding environment.
Based on this study, new EHT images reveal that the same may be true for Sagittarius A*.
“What we’re seeing now is a strong, twisted, organized magnetic field near the black hole at the center of the Milky Way,” said astronomers at the Harvard University & Smithsonian Center for Astrophysics. said Dr. Sarah Isaun.
“In addition to having a polarization structure that is strikingly similar to that seen in the much larger and more powerful M87* black hole, Sagittarius A* has a polarization structure that is strikingly similar to that seen in the much larger and more powerful M87* black hole. We found that strong, well-ordered magnetic fields are important for how they act.”
Light is a vibrating or moving electromagnetic wave that allows us to see objects. Light can oscillate in a particular direction, which scientists call polarization.
Polarized light is all around us, but to the human eye it is indistinguishable from “normal” light.
In the plasma around these black holes, particles swirling around magnetic field lines impart a polarization pattern perpendicular to the magnetic field.
This will allow astronomers to see in clearer detail what’s happening in the black hole region and map its magnetic field lines.
“By imaging polarized light from glowing gas near a black hole, we are directly inferring the structure and strength of the magnetic field that flows through the streams of gas and matter that the black hole feeds and ejects.” said Dr. Angelo Ricarte. Astronomer at Harvard University and the Harvard & Smithsonian Center for Astrophysics.
“Polarized light can tell us much more about astrophysics, the properties of the gas, and the mechanisms that occur when black holes feed.”
But imaging black holes under polarized light isn’t as easy as wearing polarized sunglasses. This is especially true for Sagittarius A*. Sagittarius A* changes so quickly that you can’t stand still and take a photo.
Imaging supermassive black holes requires sophisticated tools beyond those previously used to capture a more stable target, M87*.
“Sagittarius A*s are like enthusiastic toddlers,” said Avery Broderick, a professor at the University of Waterloo.
“For the first time, we see invisible structures that guide matter within a black hole’s disk, drive plasma to the event horizon, and help the plasma grow.”
“Sagittarius A* moves around while trying to photograph it, so it was difficult to even construct an unpolarized image,” said astronomer Dr. Jeffrey Bower of the Institute of Astronomy and Astrophysics, Academia Sinica in Taipei. Told.
“The first image is an average of multiple images from the movement of Sagittarius A*.”
“I was relieved that polarized imaging was also possible. Some models had too much scrambling and turbulence to build polarized images, but nature isn’t that cruel. did.”
Professor Maria Felicia de Laurentiis, University of Naples Federico II, said: “Using samples of two black holes with very different masses and host galaxies, we can determine what they agree on and what they do not agree on.” It’s important.
“Since both point us toward strong magnetic fields, this suggests that this may be a universal and perhaps fundamental feature of this type of system.”
“One similarity between these two black holes could be a jet. But while we imaged a very obvious black hole in M87*, we have yet to find one in Sagittarius A*. not.”
The results of this research are published in two papers (paper #1 & paper #2) in Astrophysics Journal Letter.
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Collaboration with Event Horizon Telescope. 2024. Horizon telescope results for the first Sagittarius A* event. VII. Polarization of the ring. APJL 964, L25; doi: 10.3847/2041-8213/ad2df0
Collaboration with Event Horizon Telescope. 2024. Horizon telescope results for the first Sagittarius A* event. VIII. Physical interpretation of polarization rings. APJL 964, L26; doi: 10.3847/2041-8213/ad2df1
Source: www.sci.news
