Study Shows Interaction Between Galaxies Drives Quasar Formation
In an article published in the journal Monthly Notices of the Royal Astronomical Society , researchers from the Universities of Sheffield and Hertfordshire in England analyzed images from the Isaac Newton Telescope on La Palma and found that the interaction between two galaxies is the main cause of the formation of a specific type of quasar.
According to Zulema Abraham, astronomer and professor at the Department of Astronomy at the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) at USP, quasars are “active galaxy nuclei”, that is, supermassive black holes located in the center of a galaxy, consuming matter.
The professor, who did not participate in the international research, clarifies that the new article confirmed one of the hypotheses that explain the formation of quasars, the interaction between two galaxies. “They observed 48 quasars, checking whether their host galaxies showed any deformation or irregularity due to interaction with other galaxies,” she explains.
The gravitational attraction force of these structures is so intense that it accelerates the matter approaching them at very high speeds. This generates an immense amount of energy, making quasars brighter than their own galaxies. According to the professor, a black hole becomes a quasar when “there is a large amount of matter falling into the black hole. And the problem is where does this matter come from”.
The study, however, does not reveal the origin of all quasars. In view of this, she points out that the article studies “local type 2” quasars, which emit few radio waves when compared to their counterparts. The expert also points out that there are quasars that are composed of two black holes. “It could be that they formed due to the collision of two galaxies, or it could be that two black holes formed in the same galaxy”, she theorizes.
Despite the new discovery, until scientists can understand the origin of black holes, the formation of quasars remains, partially, a mystery. “One of the key things today is [understanding] the origin of black holes. It is not known if these supermassive black holes formed at the beginning of the Universe or if they originated after the formation of galaxies”, recalls the astronomer.