Black holes come in three shapes: the size of a star, something that can be formed by a supernova to go to a star; Billions of supermassive black holes, if not billions, are located at the mass of the Sun and at the core of the galaxy; and the middle is any black hole. Since they do not emit light, all black holes are very elusive, but mid-mass black holes in particular so we have only a few potential candidates. Astronomers thought they had found a global cluster at the center of NGC 6397.
As reported in astronomy and astronomy, the motion of stars in a global cluster suggests the presence of a huge, dense, and still invisible “something” in the center. This usually gives an indication that a black hole may be hiding there. An estimated mass one thousand and two thousand times larger than the Sun, if it were a single object, would form a mid-mass black hole. In addition, that ‘if’ is important. The researchers studied the motion in the globular cluster in detail and it shown that this huge concentration in its core did not come from a single source but from a larger distribution. This indicates the presence of multiple black holes revolving in the center of the cluster. “We have found very strong evidence for an invisible mass in the dense core of a globular cluster, but we are surprised to learn that this extra mass is not ‘point-like’ (this would be expected for a huge black hole alone) but has expanded to a few percent of cluster size.” Eduardo Vitral, co-author of the Paris Institute of Astrophysics (IAP), said in a statement.
The key to the structure of the globular cluster is a special process called dynamic friction. Over the ages, the gravitational interaction between the bodies of the sky in the globular cluster separates the larger objects (pushed towards the center) from the lighter ones (which thrown towards the edges did.
The work made possible by the combined observation of the Hubble Space Telescope and the Gaia observations of the European Space Agency. Before Hubble, NGC 6397 measured 7,800 light-years from Earth with incredible accuracy.
The new work provides insights into the motions and orbits of stars, enabling researchers to establish the mass of the black hole group, and the fact that it is not a single object. Gary Mammon, co-author of IAP, further explained, “Our analysis indicates that the orbits of the stars are not regularly notified or prolonged, but are randomly close across the entire globe.” These two researchers believe that these black holes are likely to merge in the future, emitting gravitational waves that can identify by observations of the Earth.