Distorted magnetic field seen around the black hole at the center of the Milky Way | Astrophysics

An international team of astrophysicists has detected a magnetic field strong and organized, distwisted in a spiral around the Milky Way’s supermassive black hole, revealing previously unknown qualities of this tremendously powerful object hidden at the center of our galaxy.

The structure of the magnetic field emanating from the edge of the black hole called Sagittarius A* (or Sgr A*) closely resembles that surrounding the only other black hole ever photographed, which resides at the center of a nearby galaxy called Messier 87 ( or M87), astrophysicists announced this Wednesday.

This indicates that strong magnetic fields may be a common feature of black holes, added the team, which published the results.results in the magazine Astrophysical Journal Letters.

The magnetic field surrounding the black hole at the center of the M87 galaxy, M87*, allows it to launch powerful jets of material into space, researchers said. This indicates that, although such jets have not been detected so far around Sagittarius A*, they may exist –​ and could be observable in the near future.

Astrophysicists have now released a new image that shows for the first time the environment around Sagittarius A* in polarized light, revealing the structure of the magnetic field. Polarized light comes from electrons, particles subatomic, that revolve around magnetic field lines.

O Sagittarius A* is four million times the mass of our Sun and is located about 26,000 light-years away from Earth. Its image, or more precisely, the image of its shadow was obtained for the first time in 2022, after such an unprecedented feat was achieved in 2019 for the black hole at the center of the galaxy M87.

“For some time, we believed that magnetic fields played a fundamental role in the way black holes feed and eject matter in powerful jets,” said astronomer Sara Issaoun, of the Harvard-Smithsonian Center for Astrophysics (in the United States) and co-leader of the investigation.

“This new image, together with a polarization structure very similar to that observed in the M87* black hole, which is much bigger and more powerful, shows that strong, orderly magnetic fields are crucial to how black holes interact with the gas and matter around them”, added Sara Issaoun.

Black holes are extraordinarily dense objects, with gravity so strong that not even light can escape once it falls into these objects, which makes viewing them extremely difficult.

“The magnetic field appears to be organized in a spiral, similar to that of M87*. This magnetic field geometry implies that the black hole can power very efficient jets fired into the galaxy.”said another of the researchers, astronomer Angelo Ricarte, from the Center for Astrophysics in Harvard-Smithsonian.

The new image, like previous images of Sagittarius A* and black hole M87, was obtained using the Event Horizon Telescope (EHT), a global network of observatories that work collectively to observe sources radio signals associated with black holes.

The event horizon of a black hole is the point of no return beyond which everything – stars, planets, gas, dust and all forms of electromagnetic radiation – is dragged into oblivion.

When a black hole feeds

“By imaging polarized light from glowing hot gas near black holes, we are directly inferring the structure and strength of the magnetic fields that accompany the flow of gas and matter that the black hole feeds on and ejects.”explained Sara Issaoun.

“Compared to previous results, polarized light teaches us much more about astrophysics, the properties of gas and the mechanisms that occur when a black hole feeds.”added the astrophysicist.

Light is an oscillating electromagnetic wave that allows objects to be seen. Sometimes the light oscillates in a specific orientation, which is called polarized light.

The black hole M87 has a mass six billion times that of our Sun and is housed in the center of a giant elliptical galaxy. Projects a powerful plasma jet – gas so hot that some or all of its atoms split into subatomic particles, electrons and ions – visible at all wavelengths.

Evidence of the existence of a jet from Sagittarius A* is increasing, researchers said. “One thing that excites us a lot is the prediction of the existence of a powerful jet. As our instrumentation improves in the coming years, if it exists, we should be able to extract it from the data”, predicts Angelo Ricarte.