The supermassive black hole at the center of the Milky Way is in constant turmoil, showing no signs of rest.

At the center of our Galaxy lies the supermassive black hole Sagittarius A*. For scientists, this presents a remarkable opportunity to observe from close range how it emits, absorbs, and ejects matter. The accretion disk of Sagittarius A* is inflated by winds from young, mass-losing stars. What transpires in this turbulent region remains somewhat unclear. Now, researchers have unveiled the findings from the most extensive and detailed study of the Milky Way's center, conducted by NASA's James Webb Space Telescope in 2023-2024.

2025-02-19 10:03:01https://naked-science.ru/article/astronomy/sverhmassivnaya-chernaya

To observe Sagittarius A*, a team of astrophysicists from the United States, led by scientists from Northwestern University, utilized the near-infrared camera NIRCam of the James Webb Space Telescope. This instrument is capable of monitoring very faint objects with long exposure times. The results of this research have been published in the journal The Astrophysical Journal Letters.

The NIRCam camera observed the center of the Galaxy for intervals ranging from eight to ten hours over the course of a year, totaling 48 hours. This helped recreate a picture of the changes in the black hole over time. It turned out to be more active than researchers had anticipated.

The accretion disk around the black hole continuously emitted "fireworks" of varying brightness and duration. Some were faint flickers lasting just a few seconds, while others were dazzlingly bright, daily eruptions. There were also very weak flickers that smoldered for months.

"This is how all supermassive black holes behave, but ours is unique. It is always active and never reaches a steady state. We observed it several times during 2023 and 2024, and we always saw changes. It never remained the same," noted Farhad Yusef-Zadeh from Northwestern University, the lead author of the paper.

The researchers did not observe any patterns in the black hole's activity. They did not fully understand the processes occurring, but they speculated that the short and long flares might have different origins. If we imagine the accretion disk as a river, the short bursts are like random ripples, while the longer flares resemble tidal waves caused by more powerful events.

According to Yusef-Zadeh, small disturbances in the accretion disk likely lead to the faint flickers. They can be compared to solar flares.

Bright radiation flares may arise from magnetic reconnection. This refers to the collision of two magnetic fields, during which energy is released in the form of accelerated particles.

The scientists discovered another unusual phenomenon. Brightness changes observed at a wavelength of 4.8 microns lagged 3-40 seconds behind changes at 2.1 microns. This can be explained by the fact that particles at shorter wavelengths lost energy more quickly during the flare than those at longer wavelengths. This behavior is typical of particles rotating around magnetic field lines.

Further work requires extending the duration of continuous observations of Sagittarius A*. Yusef-Zadeh and his colleagues have already submitted a request for 24-hour sessions.