Black holes are the most powerful and extreme things in the universe and are wildly weird and complicated. Understanding them takes a lot of research and effort but they reveal numerous pieces of information that transform human understanding about the unknown cosmos.
In a recent feat, Indian researchers have discovered three supermassive black holes from three galaxies merging to form a triple AGN (Active Galactic Nucleus). A supermassive black hole at the center of a galaxy is called an AGN. This region of the galaxy is compact and is usually more luminous than the other parts of the galaxy.
Why is the discovery Important?
The interesting part of the research is that the team has detected a triple AGN as several active AGNs have been identified in the past, but triple AGN are extremely rare in space. To date, a handful of the triple AGNs have been detected using X-ray observations.
The discovery of the merging black holes in the nearby galaxy indicates that rare occurrences in Space like that are ideal situations to detect multiple accreting supermassive black holes.
How was the discovery made?
Jyoti Yadav, Mousumi Das, and Sudhanshu Barway (A team of researchers from the Indian Institute of Astrophysics) along with Francoise Combes of College de France, Chaire Galaxies et Cosmologie, Paris, were studying a known interacting galaxy pair, NGC7733, and NGC7734.
During the observations, the team detected unusual emissions from the center of NGC7734 and a large, bright clump along the northern arm of NGC7733. Further looking into the detection, it showed that the clump is moving with a different velocity compared to the galaxy NGC7733 itself. This indicated that this clump was not a part of NGC7733. Rather, it was a small separate galaxy behind the arm. The team named this galaxy NGC7733N.
“This study used data from the Ultra-Violet Imaging Telescope (UVIT) onboard the first Indian space observatory ASTROSAT, the European integral field optical telescope called MUSE mounted on the Very Large Telescope (VLT) in Chile and infrared images from the optical telescope (IRSF) in South Africa. The UV and H-alpha images also supported the presence of the third galaxy by revealing star formation along with the tidal tails, which could have formed from the merger of NGC7733N with the larger galaxy. Each of the galaxies hosts an active supermassive black hole in their nucleus and hence forms a very rare triple AGN system,” stated the research paper of the team which was published as a letter in the journal Astronomy and Astrophysics.
Supermassive black holes are difficult to detect
Humankind has made a long way in Astrophysics and one of the most important discoveries was the presence of Blackholes in the cosmos. These stellar masses are very hard to detect, as the name suggests ‘BLACK’, they do not emit light and thus this makes it hard to detect any Blackhole.
There are four different types of black holes – stellar, intermediate, supermassive, and miniature. The most common way of black hole formation is when a star runs out of fuel and collapses into its gravitational pull.
A way in which the universe showcases a black hole is when the black hole interacts with its surroundings. When the dust particles and matter from the surroundings fall onto a supermassive black hole, it engulfs a part of the surroundings but some of the matter is converted into energy and emitted as electromagnetic radiation that makes the black hole appear very luminous. This luminosity can be detected on earth thus, giving more insights into these stellar occurrences.