Recently, astronomers have observed the oldest known galactic merger. The collision between the two galaxies happened thirteen billion years ago.
What you see above is a composite image of a galaxy known as B14-65666, put together by a team of astronomers in Japan using the Atacama Large Millimeter/submillimeter Array (ALMA), in Chile, and the NASA-ESA Hubble Space. Researchers published it in the Journal of the Astronomical Society of Japan.
The interesting thing is that light that makes up the photograph took 13 billion years to travel to the lens of the telescope. That makes B14-65666 one of the earliest galaxies ever photographed.
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Higher-resolution data from light emitted by oxygen and carbon ions suggested the object might be a single galaxy actively forming new stars as the result of a collision. The data confirmed that the object was indeed organized into two clumps.
The study authors detected dust, carbon, and oxygen in both galactic clumps. But emissions from Clump A moved at a different velocity than the same emissions in Clump B.
This suggested that the clumps were the remnants of two galaxies that had collided in “a major merger” that was still underway.
The galaxy is about 100 times more active than the Milky Way, even though the Milky Way is the bigger galaxy by about 90%, the researchers reported.
The total mass of the entire object is about 770 million times the size of our sun.
“With rich data from ALMA and HST [Hubble Space Telescope], combined with advanced data analysis, we could put the pieces together to show that B14-65666 is a pair of merging galaxies in the earliest era of the universe,” lead study author Takuya Hashimoto, a postdoctoral researcher with the Japan Society for the Promotion of Science and Waseda University in Tokyo, said in a statement.
ALMA uses 66 ground-based antennas to detect some of the universe’s coldest and most distant objects. They observe the skies with an “eye” that is 10 times sharper than Hubble’s, according to the European Space Agency.
ALMA’s observations of B14-65666 uncovered signals that Hubble couldn’t detect.
Astronomers think that mergers are an important part of galaxy formation.