In a distant galaxy, two cores were discovered right away

UNITED STATES (OBSERVATORY NEWS) — The Cocoon Galaxy ( NGC 4490 ) is 25 million light-years from us, in the constellation Hounds of the Dogs. She interacts closely with her smaller neighbor, pulling her substance, which supports extremely active star formation in the Cocoon galaxy.

However, she herself is not so great, several times smaller than the Milky Way. Which does not prevent a distant galaxy from having not one, but two whole centers.

Previously, one nucleus of NGC 4490 was observed optical, and the other – infrared and radio telescopes. They are approximately the same in size, mass and brightness, so astronomers simply did not notice that they were dealing with two different objects.

It was only now possible to see and identify both at the same time. An article by Allen Lawrence and his colleagues at Iowa State University has been accepted for publication in The Astrophysical Journal and has so far been featured in the open online preprint library

Apparently, the presence of two active nuclei indicates that in the distant past, the Cocoon galaxy survived a merger with another galaxy of approximately equal size. This process could fill it with matter and trigger the now very active star formation. Now the merger is over, and both galactic centers have converged extremely close.

The authors note that the “dual-core” galaxy is not a unique, but a very rare case in the Universe. For example, among the 75 nearest galaxies studied by the Spitzer telescope during the SINGS project, there are none. Published in 2004, the full catalog of galaxies with a double center includes a little more than a hundred such objects.


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