In the earliest period of the universe, when it was less than a billion years old, several supermassive black holes were discovered, each with masses exceeding a billion times the mass of the Sun. These objects, known as highly luminous quasars, emit light that surpasses the brightness of an entire galaxy as they consume vast amounts of interstellar matter. The galaxies hosting these quasars often show intense star formation activity, creating hundreds to thousands of times the mass of our Sun in new stars each year. The question that intrigues scientists is what drives and sustains such accelerated growth of supermassive black holes and star formation activity.

One of the leading hypotheses suggests that gas-rich galaxy mergers are responsible for this. It is believed that during the merging of such galaxies, some of the gas is compressed, creating a large number of stars, while another part of the gas moves toward the center of the galaxy, fueling the growth of the central black hole. Recent studies indicate that such mergers are responsible for generating gravitational waves that reach us from these ancient events, providing insights into the evolution of the universe. Scientists are using new telescopes, such as the James Webb Space Telescope and the ALMA radio telescope, to investigate these processes in detail, uncovering deeper layers of interaction between gas, stars, and black holes within these galaxies. Thanks to these advanced instruments, many quasar pairs have been discovered, showing how interactions between galaxies lead to the rapid growth of supermassive black holes, even in the early stages of the universe.

Discovery of Quasar Pairs
Recent analyses of data from the Subaru Telescope, led by Associate Professor Yoshiki Matsuoka of Ehime University, have enabled the discovery of a pair of quasars approximately 12.8 billion light-years away, corresponding to the period of the "Cosmic Dawn." These quasars were significantly fainter than typical quasars from the same period, making them difficult to detect without advanced technology. Researchers believe that these quasars are in the pre-merger phase, meaning that their light has not yet reached full brightness because the black holes have not yet absorbed enough material. This pre-merger phase provides crucial information on how galaxies merge and how black holes grow in mass.

Further Research
To better understand these processes, a research team led by Takuma Izumi of the National Astronomical Observatory of Japan used the ALMA radio telescope to observe the host galaxies of the quasar pair. The results revealed that these galaxies are gravitationally attracted to each other and are on the path to merge into one. This merger will likely lead to explosive star formation and rapid growth of the supermassive black holes. One significant finding from these observations is that the gas masses in these galaxies are comparable to the gas masses in galaxies hosting highly luminous quasars, indicating that similar processes could be responsible for the formation of the most massive black holes in the universe.

Impact of Black Holes on Galaxies
Research has also shown that supermassive black holes have a profound impact on the evolution of the galaxies in which they reside. Their gravity shapes the distribution of stars and gas, and their powerful radiation can halt further star formation within the galaxy. Comparative studies have shown that black holes not only grow by accreting material from their surroundings but can also emit strong gravitational waves as they merge, further influencing the structure of galaxies. These waves, recently detected for the first time, provide evidence of the frequency of galaxy mergers throughout the history of the universe and allow astrophysicists to model these events more accurately.

Looking to the Future
The James Webb Space Telescope continues to provide new insights into these processes, allowing researchers to study even the faintest signals from deep space. Future missions, such as the Laser Interferometer Space Antenna (LISA), will further advance our understanding of gravitational waves and their role in galaxy evolution. These tools are expected to enable a more precise analysis of how supermassive black holes formed and how they shaped the universe in its earliest stages.

All these studies suggest that galaxy mergers and the growth of supermassive black holes are key to understanding the evolution of the universe. Observations using the most advanced telescopes provide us with invaluable insights into these complex processes, which have shaped the universe as we know it today. Through further research, astrophysicists hope to uncover even more secrets about these fascinating cosmic phenomena.

Source: National Astronomical Observatory of Japan