Sagittarius A*, the 4.3 million solar mass black hole at the center of the Milky Way, spins so fast that space-time around it is warped into the shape of a soccer ball, according to an analysis. Data collected by NASA's Chandra X-ray Observatory and NSF's Carl G. Jansky Very Large Array.
daily other. Sagittarius A* was found to be rotating at 60% of its maximum rotational speed, which is set by matter that cannot travel faster than the speed of light. This image shows Sagittarius A* in X-ray light from NASA's Chandra X-ray Observatory. Image credit: NASA / CXC / University of Wisconsin / Bai other.
Black holes have two fundamental properties: mass (weight) and spin (rotational speed).
Determining either of these two values ​​can tell astrophysicists a lot about black holes and their behavior.
Dr. Ruth Daly of Pennsylvania State University and colleagues applied a new method using X-ray and radio data to predict Sagittarius A*'s rotation rate based on how matter moves toward or away from the black hole. Decided.
They discovered that Sagittarius A* rotates at an angular velocity (rotations per second). Its angular velocity is about 60% of its maximum possible value, a limit set by the inability of matter to travel faster than the speed of light.
In the past, different astronomers have used different techniques to estimate the rate of rotation of Sagittarius A*, ranging from not rotating at all to rotating at near maximum speed, with mixed results.
“Our research may help answer the question of how fast our galaxy's supermassive black holes rotate,” said Dr. Daly.
“Our results show that Sagittarius A* is rotating very rapidly, which is interesting and has far-reaching implications.”
A rotating black hole pulls space-time and nearby matter into its surroundings as it rotates. Spacetime around a rotating black hole is also crushed.
If you look down at a black hole from above and follow the barrel of the jet it produces, spacetime is circular.
However, if you look at a rotating black hole from the side, spacetime looks like a soccer ball. The faster the spin, the flatter the football.
The spin of a black hole acts as an important source of energy. When a supermassive black hole rotates, its spin energy can be extracted to produce a parallel outflow, a thin beam of matter such as a jet, but this requires at least some material near the black hole. must exist.
Because of the limited fuel surrounding Sagittarius A*, the black hole has been relatively quiet for the last several thousand years, with a relatively weak jet stream.
But new research shows that this could change as the amount of material increases near Sagittarius A*.
“A collimated jet powered by a galaxy's rotating central black hole could have a significant impact on the galaxy's entire gas supply,” said Michigan State University astronomer Megan Donahue. “This also influences the rate and uniformity with which stars form.”
“Fermi bubbles seen in X-rays and gamma rays around the Milky Way's black hole indicate that the black hole was probably active in the past. Measuring the black hole's rotation is important in this scenario. It's a test.”
To determine Sagittarius A*'s spin, astronomers looked at the black hole's spin and its mass, the nature of the matter near the black hole, and its outflow properties.
The parallel outflow produces radio waves, and the disk of gas surrounding the black hole is responsible for emitting X-rays.
Using this method, the researchers combined data from NASA's Chandra X-ray Observatory and NSF's Carl G. Jansky Very Large Array with independent estimates of the black hole's mass from other telescopes. to limit the rotation of the black hole.
“Sagittarius A* offers a special perspective because it is the closest supermassive black hole to us,” said Dr. Anand Lu, an astronomer at McGill University.
“Although it is quiet now, our research shows that in the future it will have an incredibly powerful impact on the matter around it.”
“It could happen in a thousand or million years, or it could happen in our lifetime.”
of study Published in Royal Astronomical Society Monthly Notices.
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Ruth A. Daly et al. 2024. New black hole spin values ​​for Sagittarius A* obtained using the outflow method. MNRAS 527 (1): 428-436; doi: 10.1093/mnras/stad3228
Source: www.sci.news
