Everything that is happening in the universe, especially so far away, seems fascinating, including the collision of two massive galaxies that are hyper-luminous. That collision occurred right in front of astronomers’ eyes, and scientists say it reveals new information about the way everything in the universe was created.
“Discovering a hyper-luminous starburst galaxy is an extraordinary feat, but discovering two–this close to each other–is amazing,” said Dominik Riechers (as quoted by Futurity), assistant professor of astronomy and lead author on the new research study, which was published in the Astrophysical Journal. “It’s nearly 13 billion light-years away, and in its frenzied star-forming action, we may be seeing the most extreme galaxy merger known.”
This event occurred in the Southern Hemisphere’s Dorado constellation, which is also known as the swordfish. The ADFS-27 galactic pair took place about 12.6 billion light-years away from Earth, which means that the two galaxies formed when Universe was about one billion years old.
In the published paper entitled “Rise of the Titans: A Dusty, Hyper-luminous ‘870-micron Riser’ Galaxy at z~6,” Dominik A. Riechers, doctoral candidate T.K. Daisy Leung, and their colleagues report their findings as they saw the colliding galaxies. They are likely the most massive systems ever captured in the universe.
The wondrous event was observed with the Atacama Large Millimeter/submillimeter Array (ALMA), a high-elevation radio telescope in Chile. The merger picked up by the telescope started strong with ongoing star formation, which led to the growth of a “Titan” galaxy, according to the paper. According to Leung, the pair of two massive galaxies was likely formed during the early cosmic time.
“These massive systems in the early universe are showing us snapshots of their early evolution,” she said in the paper.
“Finding these galaxies — about 30,000 light-years apart — helps astronomers to understand how very extreme structures form, as they continue to birth stars and become even more massive,” added Reichers. “These galactic progenitors help us to understand massive galaxies of the present day, as we’ve tried to understand how these actually form. In other words, this discovery is helping astronomers to understand the timeline of the cosmos.”
Riechers added that they originally discovered the systems using the European Space Agency’s Herschel Space Observatory. However, it appeared as a red dot.
“Galaxies usually look bluer or greener. This one popped out because of its color. It was literally really red, which means it’s a brighter object at longer wavelengths and it is farther away than most galaxies,” Riechers explained.
Sometime earlier, the same group of astronomers used the ALMA radio telescope to examine the red dot which allowed them to see two massive galaxies with about 50 times the amount of star-forming gas that the Milky Way had. Riechers said that this huge amount of gas will convert into new stars quickly, while the pair of merging galaxies will produce stars at a “breakneck pace,” which is about 1,000 times faster than the Milky Way.
Leung added that the ALMA telescope has “revolutionized” our comprehension of young galaxies thanks to its unprecedented resolution.
“We now can see distant galaxies in exquisite detail, as we were able to uncover the compact, starburst nature of this merger pair–known only as a dusty blob in the good old days.”