A new image shows the magnetic field around a black hole in the Milky Way

In 2019, the world received for the first time look at the picture From the black hole.

Researchers with the international collaboration Event Horizon Telescope (EHT) project have zoomed into the heart of the galaxy Messier 87.

Most galaxies are thought to have black holes in the middle and they sure do: at the center of Messier 87 we saw the silhouette of a black hole, surrounded by a luminous disk.

“This is absolutely amazing, and exactly as expected,” said astronomer Justin Reeser Christiansen to forskning.no at that time.

The Event Horizon team also imaged the black hole in the Milky Way. In 2022 we got For the first time we see The giant hiding in the center of our galaxy.

Now scientists have captured a new image of the black hole in the Milky Way galaxy Sagittarius A*. The image reveals magnetic fields around the fascinating object.

The results are presented in two articles in The Astrophysical Journal Letters.

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What we see now is that there are strong, twisted, and organized magnetic fields near the black hole at the center of the Milky Way, says astronomer Sarah Isson, one of the project leaders, In a press release.

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Polarized light makes it possible to see magnetic fields

This time, astronomers with the Event Horizon project looked at Sagittarius A* in polarized light.

Electromagnetic radiation contains electric and magnetic fields that oscillate at right angles to each other and to the direction of wave propagation. Sunlight oscillates in all directions. It is non-polarized, according to Explainer video from EHT.

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When waves vibrate in the plane, light becomes polarized. It can be polarized by polarizing filters that prevent oscillations in other directions, or when it is reflected.

Hot gas in space, or plasma, emits unpolarized light. According to the video, the plasma in the magnetic fields around the black hole emits polarized light. The magnetic field acts as a polarization filter.

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Polarization enables astronomers to map the magnetic field lines in the black hole's core, according to one of them Previous article From the Event Horizon Telescope collaboration.

“By imaging polarized light from hot gas near black holes, we directly infer the structure and strength of the magnetic fields that direct the flow of gas and matter that the black hole feeds on and spews out,” says Angelo Ricarte, who also co-led the research team. project.

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See the obvious similarities

Researchers previously captured the same type of image in the polarized light of the galaxy Messier 87.

The magnetic structure is “strikingly similar” for both galaxies. This is despite the fact that the supermassive black hole in Messier 87 is much larger than the hole in the Milky Way.

The fact that the magnetic field structure of Messier 87* is very similar to that of Sagittarius A* is important. This study suggests that the physical processes that control how a black hole eats and emits a jet may be universal among supermassive black holes, says Mariafelicia de Laurentiis, a participant in the project.

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Messier 87 is a massive galaxy containing several trillion stars. From the core of the galaxy it releases a jet stream that can be seen in images. It extends over a distance of 5,000 light-years and derives its energy from the black hole at its center.

Most of the particles near the black hole are pulled out. But some of them escape, and are launched into space via jet streams, according to one of them Previous article from EHT.

The image of the black hole in Messier 87 sheds light on how these jet streams form.

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Hidden jet stream?

Similarities between images of the Milky Way's black hole and Messier 87 suggest that Sagittarius A* may have a hidden jet stream, according to the EHT.

“It is striking that the polarization structure of Sagittarius A* is very similar to the structure of the black hole in Messier 87, which we know has a massive relativistic jet,” says Ziri Younesi, a participant in the project, in a press release. From University College London.

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This exciting new study suggests the possibility of a jet stream hiding near the Sagittarius A* event horizon.

– Either there is something wrong with the measurements, or there is something wrong with the model

Great cooperation

The magnetic field around the Milky Way's black hole is about 30 times as strong as Earth's.

However, it is not very strong, almost as strong as a refrigerator magnet, says Sarah Isson For science news.

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It consists of charged particles contained in a disk of gas and dust orbiting the black hole.

The new image was captured with the help of eight telescopes around the world. Together they form a virtual Earth-sized telescope.

300 researchers from all continents are participating in the Event Horizon project.

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References:

The Event Horizon Telescope collaboration, among others: « First Event Horizon Telescope results for Sagittarius A*. Seventh. Ring polarization», The Astrophysical Journal Letters, March 27, 2024.

The Event Horizon Telescope collaboration, among others: « First Event Horizon Telescope results for Sagittarius A*. Eighth. Physical interpretation of a polarized ring», The Astrophysical Journal Letters, March 27, 2024.

(The article was first published by forskning.no)