NASA ‘s Chandra X-ray Observatory shows that a supermassive black hole at the center of H1821+643, a quasar about 3.4 billion light-years distant from Earth, rotates at about half the speed of Earth. light; it spins slower than most of its smaller cousins.
The reason, unknown
Supermassive black holes contain millions or even billions of times more mass than the Sun. Astronomers believe that almost all large galaxies have a supermassive black hole at their heart. While the existence of supermassive black holes is already well known to science—we recently saw the first simulation of the Milky Way’s black hole, Sagittarius A*—scientists are still working to understand how these cosmic giants grow and evolve.
They have strong gravitational pulls, and nothing, not even light, can escape their clutches. That affects our ability to look at them and their nearby regions. One crucial piece of information is knowing how fast black holes are spinning. “Each black hole can be defined by just two numbers: its spin and its mass,” says Julia Sisk-Reynes of the Cambridge Institute for Astronomy (IoA), leader of the work published in the journal Monthly Notices of the Royal Astronomical Society. “While that sounds simple enough, calculating those values for most black holes has turned out to be incredibly difficult.”
According to the data, this actively growing black hole contains between 3 and 30 billion solar masses , making it one of the most massive known. Sagittarius A*, by contrast, has a mass of about 4 million solar masses.
spin slower
The astronomers analyzed data from NASA’s Chandra X-ray Observatory. They found that the supermassive black hole H1821+643 is located in the bright spot at the center of the radio and X-ray emission. Because a spinning black hole drags space with it and allows matter to orbit closer to it than it which is possible for a non-rotating one, the X-ray data can show how fast the black hole in question is spinning.
Studies of the spectrum of H1821+643 show that the black hole’s rotational speed is bizarre, compared to less massive ones that rotate at close to the speed of light; something that surprised the team.
Is it because of his way of increasing in size?
This relatively slow spin supports the idea that the most massive black holes, like H1821+643, experience most of their growth by merging with other black holes, or because gas is pulled inward in random directions when their large disks break apart. . Supermassive black holes that grow in this way are likely to often undergo large spin changes, including slowing down or twisting in the opposite direction, experts say. Therefore, “the prediction is that more massive black holes should be observed to have a wider range of spin rates than their less massive relatives.”
This is the most massive black hole with an accurate spin measurement and it gives clues as to how some of the largest black holes in the universe grow. Perhaps this will give us an idea of what will happen to the supermassive black hole in our galaxy billions of years from now when the Andromeda galaxy collides with the Milky Way and other galaxies.
Referencia: Júlia Sisk-Reynés et al. 2022. Evidence for a moderate spin from X-ray reflection of the high-mass supermassive black hole in the cluster-hosted quasar H1821+643. MNRAS 514 (2): 2568-2580; doi: 10.1093/mnras/stac1389
