Awesome! THREE supermassive black holes merging; making the impossible happen
Not one, not two, as many as three supermassive black holes, and that too from three different galaxies, are merging to form a triple active galactic nucleus, researchers have discovered. This is a region at the centre of a newly discovered galaxy that has extremely high luminosity. The notable fact here is that merging of 2 black holes is impossible, but adding a third into the equation makes it possible, according to researchers.
The reason behind this luminosity is that when the black hole sucks up the dust and gas from the surroundings, some of the mass is swallowed by the black hole. However, some of it is converted into energy and emitted as electromagnetic radiation and this makes the black hole seem to be very bright, when the exact opposite should be happening.
"Supermassive black holes are difficult to detect because they do not emit any light. But they can reveal their presence by interacting with their surroundings," the Department of Science and Technology said on Friday.
What the researchers saw
Researchers were actually studying a known interacting galaxy pair, NGC7733, and NGC7734, when they detected unusual emissions from the centre of NGC7734 and a large, bright clump along the northern arm of NGC7733. Their investigations showed that the clump is moving with a different velocity compared to the galaxy NGC7733 itself.
The scientists realised that this clump was not a part of NGC7733; rather, it was a small separate galaxy and they proceeded to name it NGC7733N.
"They are called active galactic nuclei (AGN) and release huge amounts of ionised particles and energy into the galaxy and its environment. Both of these ultimately contribute to the growth of the medium around the galaxy and ultimately the evolution of the galaxy itself," the study showed.
During such galaxy interactions, these supermassive black holes can get near each other. The dual black holes start consuming gas from their surroundings and become dual AGN.
The IIA team explains that if two galaxies collide, their black holes will also come closer by transferring the kinetic energy to the surrounding gas.
The problem of the black holes merger
The distance between the black holes decreases with time until the separation is around a parsec (3.26 light-years). The two black holes are then unable to lose any further kinetic energy in order to get closer and merge. This is known as the final parsec problem.
The presence of a third black hole can solve this problem. The dual merging black holes can transfer their energy to the third black hole and merge with each other, the DST said.
The researchers concerned are from the Indian Institute of Astrophysics and includes Jyoti Yadav, Mousumi Das, and Sudhanshu Barway along with Francoise Combes of College de France, Chaire Galaxies et Cosmologie, Paris.