Astronomers discover the merger of quasars in the “cosmic dawn”

Using the Gemini North telescope, an international team of astronomers has made a record-breaking observation Quasars explore. Not only are they the most distant pair of merging quasars ever discovered, they are also the only pair of quasars so far in the so-called reionization epoch (Astrophysical Journal LettersJune 17).

The universe has been expanding since the first moment after the Big Bang. This means that the early universe was much smaller, and the first galaxies were closer together and merged more easily. This process led to the formation of quasars: the centers of extremely bright galaxies, where gas and dust fall toward a central supermassive black hole, emitting enormous amounts of light. If you looked deep into the universe, you would expect to see many pairs of quasars, but so far, to the astonishment of astronomers, they have yet to be found.

However, using the GNIRS instrument on the Gemini North Telescope, astronomers have now been able to track down the pair of merging quasars we observe when they appeared just 900 million years after the Big Bang, in an epoch called cosmic dawn.

The cosmic dawn lasted from about fifty million years to a billion years after the Big Bang. During this period, the first stars and galaxies appeared on the cosmic stage, filling the previously dark universe with light for the first time. The arrival of the first stars and galaxies heralded a new era in the formation of the universe: the era of reionization. During this period, ultraviolet light from the first stars, galaxies, and quasars stripped the hydrogen atoms in the universe of their electrons—a process known as Ionization It was mentioned – and the first large structures in the universe were formed.

To understand the role quasars played in this ionization process, astronomers have been searching for distant (and therefore early) examples of these objects for years. About three hundred reionization epoch quasars have been discovered so far. In addition, a team led by Yoshiki Matsuoka of Ehime University in Japan stumbled upon an extremely distant double quasar.

Subsequent observations have shown that the quasars in question are true giant objects, each 100 million times the mass of our Sun. This, combined with the presence of a “bridge” of gas running between the two stars, suggests that they and the two galaxies of which they are part are undergoing a large-scale merger. (any)

International Gemini Observatory and Subaru join forces to discover first pair of merging quasars in Cosmic Dawn