The first observation of the last stages of merging galaxies

A team of astronomers have made a great study of colliding galaxies, approximately one fifth of which were in the last stages of the merger.

Проведено первое наблюдение последних стадий слияния галактик

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Astronomers first studied the final stage of merging galaxies, watching through the dense layers of gas and dust for the convergence of a pair of supermassive black holes and their rapid growth. A new study described in an article for the journal Nature.

According to the models of merging galaxies provide supermassive black holes great opportunity to tear apart the stars and absorb matter. Such processes produce a very strong radiation, and also are probably the driving force behind the quasars are among the brightest objects in the Universe.

However, the authors of a new study claim that not all supported model for galactic mergers of supermassive black holes. While some works have pointed out the connection between quasars and colliding galaxies, other studies this relationship was not found.

Проведено первое наблюдение последних стадий слияния галактик

Examples witnessing the last stages of the merger / © M. Koss/NASA/ESAW.M. Keck Observatory/Pan-STARRS

Now scientists were able to observe several pairs of galaxies that are in the later stages of merging, in the process of aligning their Central supermassive black holes. New data has shed light on how can appear even more massive black holes.

The researchers first engaged in the search for hidden black holes, after examining the x-ray data collected over 10 years orbital Observatory Swift. When black holes absorb matter, such “active” black holes produce high-energy x-ray radiation, which is visible even through the dense clouds of gas and dust.

Then scientists found galaxies that are coincident with this x-ray data, after examining the pictures of the Hubble telescope and the Keck Observatory in Hawaii. Adaptive optics the Keck Observatory has helped to significantly improve the sharpness of the images of stars.

The researchers analyzed 96 galaxies observed at Keck Observatory, and 385 of galaxies from the archive of Hubble. They are all located on average 330 million light years from Earth — relatively close in astronomical terms, and many of them are similar to the milky Way.

The researchers found that more than 17% of galaxies had a pair of black holes at their center. Therefore, these galaxies were already in the final stages of a merger. These data coincide with computer simulations, scientists, suggesting that highly active, but hidden black holes in galaxies, rich in gas and dust, responsible for many mergers of supermassive black holes.

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