Observation of the most distant black hole collision ever recorded, when the Universe was only 740 million years old

With its state-of-the-art instruments, the James Webb Space Telescope is capable of observing the details galaxies very far. He recently discovered a great primitive event, when the universe was only 740 million years old. Through the images taken by the telescope, scientists were able to detect the collision of the two
Black holes, which would therefore be the furthest discovered so far. Analysis of the phenomenon should deepen our understanding of the mechanism behind the rapid mass growth of these objects.

Over the past decade, two interferometers (devices for measuring distances or optical properties with high precision), Ligo and Virgo, have detected about a hundred gravitational wave events from cosmic collisions. These phenomena are therefore far from rare. However, recently the James Webb Space Telescope was able to observe one of these events when the universe was only 740 million years old.

The phenomenon was observed in a galactic system called ZS7, whose stellar mass would be similar to that of the Large Magellanic Cloud, our galaxy neighbor. “Thanks to the unprecedented sharpness of the images taken by the James Webb Space Telescope, we were able to spatially separate two black holes“, says Hannah Übler, astronomer from the University of Cambridge, d communicated European Space Agency (ESA).

Two black holes 50 million times more massive than the Sun

One of the black holes has an estimated mass of about 50 million times that of the Sun, which qualifies it as a black hole supermassive. To obtain this measurement, scientists analyze the radiation emitted by the environment. The latter is the result of the heating of the surrounding matter inside the accretion disk, which emits X-rays and other wavelengths of extreme intensity.

As for the second black hole, it was more difficult for scientists to estimate its mass. Indeed, it is surrounded by a dense cloud of gas that hinders direct observations. “We found evidence of very dense gas near a black holeÜbler explains. This element could absorb or emit radiation, thus masking the specific signatures of the black hole and making estimation difficult. However, astronomers estimate that it could have the same mass as the first one.

Towards a better understanding of black holes

This phenomenon could help scientists better understand the growth of supermassive black holes. You should know that one of the great mysteries of cosmology lies in the mechanisms that cause these cosmic sinkholes to reach such colossal masses. So far we only know that they grow by absorbing the surrounding matter (gas, stars, dust) at an extremely high speed. Researchers also think that supermassive black holes are already born nearly as massive. However, there is a lack of data to support this hypothesis.

Another hypothesis suggests that black holes also grow rapidly mainly by merging with other very massive cosmic objects (black holes, stars neutrons). According to astrophysicists, the images recently provided by Webb do not provide concrete evidence to support either of these explanations, but they will help to better understand the mechanisms mentioned in the latter hypothesis.