Rare Merger of Three Jumbo Black Holes

Rare Merger of Three Jumbo Black Holes

Question: In which of the following constellation a team of astrophysicists in India have recently spotted a rare merging of three Supermassive Black Holes?
a) Toucan
b) Hydra
c) Ursa Major
d) The big bear
Answer: (a)
Related Facts:-

  • A team of astrophysicists in India have recently spotted a rare merging of three Supermassive Black Holes.
  • These black holes have been observed in the centers of three galaxies located in the Toucan constellation.
  • The discovery came when the astrophysicists from Indian Institute of Astrophysics were observing the merging of two galaxies.
  • These merging galaxies were named as NGC7733 and NGC 7734 and located in our celestial neighborhood.
  • Astrophysicists detected unusual emissions from the centre of the NGC 7734 when they found the curious movement of a large bright clump within it.
  • They found that this new clump of light is nothing but a new galaxy having a different velocity than that of NGC7733.
  • After confirming with some other observations that this was a separate galaxy, the scientists named it NGC7733N.
  • There are Supermassive black holes, which are several million solar masses in size, at the centres of these galaxies.
  • These black holes are known as Active Galactic Nuclei, since the black holes accrete matter; they often have a glow around them.
  • It should be known that the Glow around a black hole can be observed using light spectroscopy.
  • The report about these black holes was published in the journal Astronomy and Astrophysics.
  • According to the author of the paper the discovery happened by chance during the observation of barred spiral galaxies NGC7733 and NGC7734.
  • Astronomers said that they were studying the active galactic nuclei in these two massive galaxies which surprisingly led them to the detection of the third.
  • Final Parsec Problem
  • The Astronomers explained that if two galaxies collide, their black hole will also come closer by transferring the kinetic energy to the surrounding gas.
  • 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 to get even closer and merge. This is known as the final parsec problem.
  • Now as the astronomers detected the third black hole near these two, there is no problem now.
  • The two can come closer when another black hole or a star passes by and takes away some of their combined angular momentum
  • Thus, the dual merging black holes will merge with each other in the presence of a third.

By Rajesh Tripathi

Links:-
https://www.thehindu.com/sci-tech/science/indian-astrophysicists-spot-rare-merger-of-three-jumbo-black-holes/article36132122.ece