The analysis of data collected by the XMM-Newton X-ray telescope allowed the researchers to detect a deceptively “quiet” black hole. Its latent activity affects star formation processes throughout the galaxy.
How black holes affect their galaxies
At the center of almost every large galaxy is a supermassive black hole, whose powerful gravity draws in gas from the surrounding environment. As the gas spirals, it accumulates into a flat accretion disk. The substance in it is ground, heated to enormous temperatures, which is accompanied by the release of a large amount of energy, and then passes the point of no return and is absorbed.
However, black holes do not absorb all the gas from the accretion disk. Part of the substance is thrown back. This usually occurs in the form of two polar jets (jets). But in some cases, matter from the accretion disk is ejected in all directions at such a speed that it sweeps away the surrounding interstellar gas. This not only deprives the black hole of food, but also leads to the fact that new stars can no longer form in the vast region in its neighborhood, which changes the structure of the galaxy.
So far, this ultrafast “wind” of a black hole has been detected only in very bright accretion disks that are at the limit of their ability to draw in matter. But thanks to the XMM-Newton X-ray telescope, astronomers were able to detect this effect in an ordinary galaxy.
The “quiet” galaxy
The discovery was made during the study of the Markarian 817 galaxy. It attracted the attention of researchers with its “silence” – very little X-ray radiation came out of its center. Later it turned out that the reason for this was the wind created by a supermassive black hole. It acted as a shroud, blocking the radiation coming from the black hole’s immediate surroundings.
A detailed analysis of the X-ray measurements showed that despite the apparent calm, the black hole in Markarian 817 produced very powerful winds, and this lasted for at least a year.
The discovery helps astronomers answer the question of how black holes affect their surroundings. Many galaxies, including the Milky Way, have large regions around their centers in which very few new stars form. This can be explained by the winds of black holes that wash away star-forming gas. Previously, it was believed that this required an extremely active black hole with a massive accretion disk. But now it has become clear that even a black hole that absorbs a moderate amount of matter can have a very significant impact on its galaxy.
