Astronomers have detected a pair of galaxies merging 12.8 billion years ago. The features of these galaxies suggest that their merger will create a colossal galaxy, recognized as one of the brightest entities in the Universe.
Astronomers have detected a pair of galaxies merging 12.8 billion years ago. The features of these galaxies suggest that their merger will create a colossal galaxy, recognized as one of the brightest entities in the Universe. This discovery is crucial for grasping the early development of galaxies and black holes in the nascent Universe.
Quasars, which are incredibly bright objects, are energized by matter that falls into a supermassive black hole located at a galaxy’s center during the Universe’s early days. The prevailing theory posits that when two gas-rich galaxies collide to become a larger galaxy, their gravitational pull draws gas toward the supermassive black hole in one or both galaxies, triggering quasar activity.
To explore this theory, an international team of researchers led by Takuma Izumi utilized the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope to investigate the earliest known pair of close quasars. This pair was identified by Yoshiki Matsuoka at Ehime University in Japan through images captured by the Subaru Telescope. Positioned in the direction of the Virgo constellation, this pair existed within the first 900 million years of the Universe. Their faintness suggests that the quasars are still in their early evolutionary phases. Observations from ALMA mapped the host galaxies, revealing a “bridge” of gas and dust connecting them. This confirms that the two galaxies are indeed merging.
Additionally, ALMA’s observations enabled the research team to gauge the gas quantity, the essential ingredient for forming new stars. They discovered that both galaxies are abundant in gas, indicating that, alongside an increase in quasar activity, the merger will also lead to a rapid rise in star formation, a phenomenon referred to as a “starburst.” The fusion of starburst activity and powerful quasar activity is predicted to give rise to an exceptionally bright object in the early Universe, termed a monster galaxy.
