Astronomers have caught a glimpse into the early universe with the discovery of a rare galaxy merger that occurred 12.8 billion years ago. Utilizing the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope, researchers have observed an extraordinary cosmic event involving a pair of galaxies that are on the brink of creating a monster galaxy characterized by intense quasar activity and a burst of star formation.
Title: Dancing Galaxies at the Cosmic Dawn – An artist’s impression of the interacting galaxies observed in this study. The gravitational interaction during the merger triggered a starburst and quasar activity. Credit: ALMA (ESO/NAOJ/NRAO), T.Izumi et al.
This early universe event is of paramount importance for understanding the formation stages of galaxies and black holes in the cosmos.
The galaxies involved in this merger exhibit characteristics that suggest they will eventually form a massive galaxy, one of the brightest objects in the universe. These findings are crucial for understanding the early evolution of galaxies and black holes in the early universe.
Quasars are luminous celestial objects powered by the accretion of material into supermassive black holes at the centers of galaxies. The most widely accepted theory posits that when two gas-rich galaxies merge to form a larger galaxy, the gravitational interaction between them causes gas to fall toward one or both of the supermassive black holes, triggering quasar activity.
To test this theory, an international research team led by Takuma Izumi used ALMA to study the earliest known pair of nearby quasars. This pair was discovered in images taken by the Subaru Telescope by Yoshiki Matsuoka of Ehime University in Japan.
The quasar pair is located in the direction of the Virgo constellation and exists within the first 900 million years of the universe. The pair is faint, indicating they are still in the early stages of their evolution. ALMA’s observations have mapped the host galaxies of the quasars and revealed that the two galaxies are connected by a bridge of gas and dust. This suggests that the galaxies are indeed merging.
Through ALMA observations, the research team also measured the amount of gas necessary for new star formation. They found that the galaxies are rich in gas, indicating that not only will quasar activity intensify in the future, but the merger will also trigger a rapid increase in star formation, known as a starburst. The combination of starburst activity and active quasar activity is expected to form an extremely bright object in the early universe, termed a monster galaxy.
The discovery of this galaxy merger provides invaluable insights into the processes that shape the structure and evolution of the universe. It offers a rare glimpse into the early stages of galaxy formation, a period that is often obscured by the vast distances and time scales involved.
The detection of this galaxy merger is a significant step forward in our understanding of the early universe, said Dr. Takuma Izumi, the lead researcher. It not only confirms our theoretical models but also provides us with a unique opportunity to observe the birth of a monster galaxy firsthand.
The research team plans to continue observations with ALMA to further study the properties of the merging galaxies and their quasars, aiming to uncover more details about the processes that drive galaxy evolution in the early cosmos.
This groundbreaking discovery, made possible by the powerful capabilities of ALMA and the dedication of international astronomers, underscores the importance of continued exploration and study of the universe. As we delve deeper into the mysteries of the cosmos, each new discovery brings us closer to unraveling the secrets of our origins.
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