Astronomers have discovered the oldest compact pair of quasars
In the early universe, supermassive black holes already existed, which managed to grow to enormous sizes in just a few hundred million years after the Big Bang. Now astronomers have found two such black holes located unusually close to each other. They existed when the universe was only 900 million years old, and their mass reached hundreds of millions and billions of times the mass of the Sun. About why the discovery calls into question modern ideas about the growth of black holes — in the material of "Izvestia".
A pair of giants at the dawn of the Universe
An international team of astronomers has discovered the J1602+4228AB system, which has received the Hawaiian name Nāpōwawā'enakaulua. It has become the oldest and most compact pair of quasars known to date. At the same time, this is only the third discovered pair of similar objects that existed in the era of the cosmic dawn — in the first 1 billion years after the Big Bang.
The results of the study led by Silvia Onorato from the National Research Laboratory of Optical and Infrared Astronomy of the USA (NSF NOIRLab) are published in The Astrophysical Journal Letters (AJL). The scientists used data from the James Webb Space Telescope (JWST) and the Gemini North ground-based telescope.
A quasar is an extremely bright active galactic nucleus. At its center is a supermassive black hole that consumes the surrounding gas and other substances. At the same time, matter heats up and releases a huge amount of energy, so that the quasar can shine brighter than all the stars in its galaxy.
The discovered pair is located at a distance of about 18.1 thousand light-years from each other, which is about a fifth of the diameter of the Milky Way. The mass of one black hole is about 1.5 billion solar masses, the second is about 400 million.
Why the mass of black holes surprised astronomers
The main mystery of the discovery is related to the age of the system. The light from it traveled to Earth for so long that scientists are observing the pair as it was about 900 million years after the Big Bang. At that time, the first stars and galaxies were just forming, and black holes were still in the early stages of evolution.
However, both discovered black holes have already managed to gain a mass comparable to that of modern supermassive objects. According to the head of the study, Silvia Onorato, there is still no definitive theoretical explanation of how even one such giant black hole could have formed so early, let alone two.
Silvia Onorato
We observed Nakawawaenakaulua in an era when the universe was only 13 th of its current age. And, surprisingly, its supermassive black holes were already as massive as the ones we observe today.
Astronomers suggest that black holes grow by absorbing gas and stars, and can also increase their mass when merging with other black holes. But to achieve the detected size in such a short period of time, they would have to accumulate matter extremely quickly. Exactly how this process took place in the case of a new couple remains unknown.
How were two quasars discovered?
The pair was found when analyzing data from the Aether program, which uses the JWST telescope to study objects in the early Universe. As part of the review, the researchers collected data on 200 quasars, which is about 43% of all known objects of this type that existed at that time. While studying the images, scientists noticed that there is another radiation source next to the already known quasar J1602+4228A. To confirm that these are two separate objects, the team conducted additional observations using the Gemini North telescope in Hawaii.
It turned out to be difficult to separate the sources: the second quasar is much dimmer than the first and is located very close to it. From the Ground, observing them individually was an extremely difficult task. However, the researchers were helped by exceptionally favorable weather conditions at the top of the volcano Mauna Kea. Additional observations using the GMOS spectrograph made it possible to more accurately determine the characteristics of both quasars.
Silvia Onorato
The sky over Mauna Kea was so clear and transparent that we managed to collect data in just two nights.
What the pair can tell us about the early Universe
The full history of Nāpōwawā 'enakaulua remains a mystery. However, the researchers suggest that the system may point to a region of the early universe with an extremely high density of matter. In such places, interactions and collisions of galaxies could simultaneously contribute to the formation of new stars and the rapid growth of central black holes.
According to the authors of the work, the discovered pair represents a kind of laboratory for studying how the first massive galaxies and their central black holes were formed. Observations of such systems allow us to check how well modern models describe the processes in the first billions of years of the existence of space.
Silvia Onorato
Nāpōwā 'enakaulua is a truly unique environment. This is a laboratory where astronomers can study how the very first massive galaxies and their central black holes formed together due to the direct interactions of galaxies in that early era.
Thus, the discovery not only adds a new object to the catalog of ancient quasars, but also marks one of the unsolved problems of modern cosmology: scientists have to figure out how supermassive black holes could reach such sizes at such an early stage in the history of the universe.
Переведено сервисом «Яндекс Переводчик»
